Process for producing ester compound

ABSTRACT

To provide an environmentally-friendly method for producing industrially an ester compound. 
     SOLUTION 
     The present invention is a method for producing an ester compound which comprises subjecting a carboxylic acid and an alcohol to dehydration-condensation reaction using an involatile acid catalyst and then removing the residual acid catalyst by bringing a weak basic substance into contact with the residual acid catalyst.

TECHNICAL FIELD

The present invention relates to an environmentally-friendly industrialmethod for producing an ester compound.

BACKGROUND ART

Researches on an environmentally-friendly chemical process have beenlately prevalent and many reports relating to the researches onimportant esterification reaction that is valuable in use are presented.

The dehydration-condensation reaction of a carboxylic acid and analcohol using an acid catalyst is known as the most general method forproducing an ester compound and specifically includes, for example, (1)a method comprising adding concentrated sulfuric acid (acid catalyst) toa solution of a carboxylic acid and methanol in dichloroethane followedby heating and refluxing, then separating an organic layer by dilutingwith water, and neutralizing the obtained organic layer with a saturatedaqueous solution of sodium hydrogencarbonate and then distilling off thesolvent to obtain an ester (Non-patent Literature 1; ExperimentalChemistry Course (Jikken Kagaku Kouza), 1. Carboxylic acid and itsderivative, 1.2 Esters, page 44, Experimental example 1.30) and (2) amethod comprising adding concentrated sulfuric acid (acid catalyst) to amixture of benzoic acid and anhydrous ethanol followed by heating andrefluxing, then distilling off the unreacted alcohol under atmosphericpressure, and adding water of an amount of 5 times, and thenneutralizing with solid sodium carbonate, and then extracting theseparated oily material with ether, and washing the obtained ether layerwith water and distilling off the ether to obtain an ester (Non-patentLiterature 1; Experimental example 1.31), etc.

However, in case these methods is used as producing industrially anester compound, it has not been satisfactory from the standpoint ofgreen chemistry because these methods have the problem that a largeamount of water is used for an extraction treatment to an organic layerand neutralization treatment for removing an acid catalyst (for example,a saturated aqueous solution of sodium hydrogencarbonate, and sodiumcarbonate and water) resulting in a large amount of waste water.

Under these conditions, development of a method for producingindustrially an ester compound taking economic efficiency andenvironment into consideration has been desired.

[Non-patent Literature 1] “New Experimental Chemistry Course 14 (ShinJikken Kagaku Kouza) Synthesis and reaction of organic compound II”edited by Corporation: The Chemical Society of Japan, published byMARUZEN CO., LTD, Dec. 20, 1977, 1. Carboxylic acid and its derivative,1.2 Esters, page 44, Experimental examples 1.30 and 1.31)

DISCLOSURE OF INVENTION Problem to be Solved by the Invention

Considering the above situations, it is an object of the presentinvention to provide an environmentally-friendly industrial method forproducing an ester compound.

Means for Solving the Problem

The present invention is an invention of a method for producing an estercompound which comprises subjecting a carboxylic acid and an alcohol todehydration-condensation reaction using an involatile acid catalyst andthen removing the residual acid catalyst by bringing a weak basicsubstance into contact with the residual acid catalyst, morespecifically a method which comprises subjecting an alcohol representedby a general formula [1]:

R¹—OH   [1]

(wherein R¹ represents an alkyl group having 1 to 18 carbon atoms, anoxygen-atom-containing alkyl group, an alkenyl group, an alkynyl group,an aryl group, an aralkyl group or a heterocyclic group, which may havea substituent)and a carboxylic acid represented by a general formula [2]:

R²—COOH   [2]

(wherein R² represents an alkyl group having 1 to 18 carbon atoms, anoxygen-atom-containing alkyl group, an alkenyl group, an alkinyl group,an aryl group, an aralkyl group or a heterocyclic group, which may havea substituent) to reaction without any solvent or in a nonaqueoussolvent in the coexistence of an involatile acid catalyst and thenadding the obtained reaction solution with a weak basic substancefollowed by removing the formed salt of the weak basic substance and theacid catalyst in the reaction solution to produce an ester compoundrepresented by a general formula [3]:

R¹—OCO—R²   [3]

(wherein R¹ and R² are the same as the above).

Effects of the Invention

The method for producing an ester compound of the present invention caneasily remove an acid catalyst in a reaction solution, without theproblems accompanied with conventional methods that many steps arenecessary for extraction, and that a large amount of water forneutralizing the acid catalyst in a water phase is uneconomical andmakes a large volume of waste water, because the neutralizationtreatment of the acid catalysit is carried out by forming a salt with aweak basic substance and removing the salt thereof, and thus the methodof the invention can industrially produce an ester compound in anefficient and environmentally-friendly manner.

BEST MODE FOR CARRYING OUT THE INVENTION

The method for producing an ester compound of the present inventionincludes, for example, a method for producing an ester compound whichcomprises subjecting a carboxylic acid and an alcohol todehydration-condensation reaction using an involatile acid catalyst andthen removing the residual acid catalyst by bringing a weak basicsubstance into contact with the residual acid catalyst, or morespecifically, for example, a method for producing an ester compoundwhich comprises subjecting an alcohol represented by a general formula[1]:

R¹—OH   [1]

(wherein R¹ represents an alkyl group having 1 to 18 carbon atoms, anoxygen-atom-containing alkyl group, an alkenyl group, an alkynyl group,an aryl group, an aralkyl group or a heterocyclic group, which may havea substituent)and a carboxylic acid represented by a general formula [2]:

R²—COOH   [2]

(wherein R² represents an alkyl group having 1 to 18 carbon atoms, anoxygen-atom-containing alkyl group, an alkenyl group, an alkynyl group,an aryl group, an aralkyl group or a heterocyclic group, which may havea substituent) to reaction without any solvent or in a nonaqueoussolvent in the coexistence of an involatile acid catalyst and thenadding the obtained reaction solution with a weak basic substancefollowed by removing the formed salt of the weak basic substance and theacid catalyst in the reaction solution to produce an ester compoundrepresented by a general formula [3]:

R¹—OCO—R²   [3]

(wherein R¹ and R² are the same as the above).

That is, the alcohol and the carboxylic acid relating to the presentinvention are not particularly limited as long as they are able toattain the purpose of the present invention. The alcohol includes, forexample, an alcohol represented by the above general formula [1] and analcohol represented by a general formula [9]:

HO-(T₁-O)_(n)—H   [9]

(wherein T₁ represents an alkylene chain having 1 to 4 carbon atoms; andn represents an integer of 1 to 5). The carboxylic acid includes, forexample, a carboxylic acid represented by the above general formula [2]and a carboxylic acid represented by a general formula [11]:

HOOC-T₂-COOH   [11]

(wherein T₂ represents an alkylene group having 1 to 8 carbon atomswhich may have a substituent or an arylene group).

In addition, the alcohol and the carboxylic acid related to the presentinvention also include a compound having a hydroxyl group and a carboxylgroup in the same compound and specifically a compound represented by ageneral formula [7]:

(wherein T represents an alkylene chain which may have a substituent)

In the general formulae [1] to [3], the alkyl group of an alkyl grouphaving 1 to 18 carbon atoms which may have a substituent represented byR¹ and R² includes any of a straight-chained, branched and cyclic group,and usually includes a group having 1 to 18 carbon atoms, preferably 1to 8 carbon atoms and specifically, for example, a methyl group, anethyl group, a n-propyl group, an isopropyl group, a n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, a n-pentyl group,an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentylgroup, a 1-methylpentyl group, a n-hexyl group, an isohexyl group, asec-hexyl group, a tert-hexyl group, a neohexyl group, a n-heptyl group,an isoheptyl group, a sec-heptyl group, a tert-heptyl group, a neoheptylgroup, a n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, a neooctyl group, a n-nonyl group, an isononyl group,a sec-nonyl group, a tert-nonyl group, a neononyl group, a n-decylgroup, an isodecyl group, a sec-decyl group, a tert-decyl group, aneodecyl group, a n-undecyl group, an isoundecyl group, a sec-undecylgroup, a tert-undecyl group, a neoundecyl group, a n-dodecyl group, anisododecyl group, a sec-dodecyl group, a tert-dodecyl group, an-tridecyl group, an isotridecyl group, a sec-tridecyl group, atert-tridecyl group, a neotridecyl group, a n-tetradecyl group, anisotetradecyl group, a sec-tetradecyl group, a tert-tetradecyl group, aneotetradecyl group, a n-pentadecyl group, an isopentadecyl group, asec-pentadecyl group, a tert-pentadecyl group, a neopentadecyl group, an-hexadecyl group, an isohexadecyl group, a sec-hexadecyl group, atert-hexadecyl group, a neohexadecyl group, a n-heptadecyl group, anisoheptadecyl group, a sec-heptadecyl group, a tert-heptadecyl group, aneoheptadecyl group, a n-octadecyl group, an isooctadecyl group, asec-octadecyl group, a tert-octadecyl group, a neooctadecyl group, acyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, acyclodecyl group, a cycloundecyl group, a cyclododecyl group, acyclotridecyl group, a cyclotetradecyl group, a cyclopentadecyl group, acyclohexadecyl group, a cycloheptadecyl group and a cyclooctadecyl groupetc.

The alkenyl group of an alkenyl group which may have a substituentrepresented by R¹ and R² includes any of a straight-chained, branchedand cyclic group, and usually includes a group having 2 to 12,preferably 2 to 8 carbon atoms and specifically, for example, a vinylgroup, an allyl group, a 1-propenyl group, an isopropenyl group, a1-butenyl group, a 2-butenyl group, a 3-butenyl group, a 2-methylallylgroup, a 1-pentenyl group, a 2-pentenyl group, a 3-pentenyl group, a4-pentenyl group, a 2-methyl-2-butenyl group, a 1-hexenyl group, a2-hexenyl group, a 3-hexenyl group, a 5-hexenyl group, a2-methyl-2-pentenyl group, a 1-heptenyl group, a 2-heptenyl group, a3-heptenyl group, a 4-heptenyl group, a 5-heptenyl group, a 6-heptenylgroup, a 1-octenyl group, a 2-octenyl group, a 3-octenyl group, a4-octenyl group, a 1-nonenyl group, a 2-nonenyl group, a 3-nonenylgroup, a 4-nonenyl group, a 1-decenyl group, a 2-decenyl group, a3-decenyl group, a 4-decenyl group, a 5-decenyl group, a 1-undecenylgroup, a 2-undecenyl group, a 3-undecenyl group, a 4-undecenyl group, a5-undecenyl group, a 1-dodecenyl group, a 2-dodecenyl group, a3-dodecenyl group, a 4-dodecenyl group, a 5-dodecenyl group, a6-dodecenyl group, a 1-cyclobutenyl group, a 1-cyclopentenyl group and a1-cyclohexenyl group etc.

The alkynyl group of an alkynyl group which may have a substituentrepresented by R¹ and R² includes any of a straight-chained, branchedand cyclic group, and usually includes a group having 2 to 12 carbonatoms, preferably 2 to 8 carbon atoms and specifically, for example, anethenyl group, a 2-propynyl group, a 2-pentynyl group, a2-nonyl-3-butynyl group, a cyclohexyl-3-ynyl group, a 4-octynyl groupand a 1-methyldecyl-5-ynyl etc.

The aryl group of an aryl group which may have a substituent representedby R¹ and R² usually includes a group having 6 to 18 carbon atoms andspecifically, for example, a phenyl group, a naphthyl group, an anthrylgroup, a phenanthryl group and a naphthacenyl group etc.

The aralkyl group of an aralkyl group which may have a substituentrepresented by R¹ and R² usually includes a group having 7 to 15 carbonatoms and specifically, for example, a benzyl group, a phenetyl group, aphenylpropyl group, a naphthylmethyl group and a biphenyl group etc.

The heterocyclic group of a heterocyclic group which may have asubstituent represented by R¹ and R² includes, for example, a 5-memberedring or a 6-membered ring, that contains 1 to 3 hetero atoms such as,for example, a nitrogen atom, an oxygen atom and a sulfur atom andspecifically, includes an aliphatic heterocyclic group such as, forexample, a pyrrolidyl-2-one group, a piperidyl group, a piperidinogroup, a piperazinyl group and a morpholino group and an aromaticheterocyclic group such as, for example, a pyridyl group, an imidazolylgroup, a thiazolyl group, a furyl group and a pyranyl group etc.

The oxygen-atom-containing alkyl group which may have a substituentrepresented by R¹ and R² includes a group having 1 to 5 oxygen atoms inthe chain of an alkyl group which may have a substituent andspecifically, for example, includes a group represented by a generalformula [13]:

(wherein R¹⁰ represents an alkyl group which may have a substituent; mpieces of T3 s indicate each independently an alkylene chain of 1 to 4carbon atoms which may have a substituent; and m represents an integerof 1 to 6).

In the general formula [13], the alkyl group of an alkyl group which mayhave a substituent represented by R¹⁰ includes any of astraight-chained, branched and cyclic group, and usually includes agroup having 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms andspecifically, for example, the similar one to the exemplification of 1to 12 carbon atoms of the alkyl groups having 1 to 18 carbon atoms whichmay have a substituent represented by R¹ and R².

The alkylene chain having 1 to 4 carbon atoms which may have asubstituent represented by T₃ usually includes a straight-chainedalkylene group having 1 to 4 carbon atom, preferably 2 to 3 carbon atomsand specifically, for example, a methylene group, an ethylene group, atrimethylene group and a tetramethylene group etc.

In the general formula [1], the substituent of the alkyl group, alkenylgroup or alkinyl group, which has a substituent, represented by R¹includes, for example, a halogen atom, a haloalkyl group, an alkoxygroup, a haloalkoxy group, a thioalkoxy group, an acyl group, asubstituted amino group, a hydroxyl group, a cyano group, a carboxylgroup, a nitrile group and a nitro group etc.

The substituent of the aryl group, aralkyl group or heterocyclic group,which has a substituent, represented by R¹ includes, for example, ahalogen atom, an alkyl group, a haloalkyl group, an alkenyl group, analkoxy group, a haloalkoxy group, a thioalkoxy group, an acyl group, asubstituted amino group, a hydroxyl group, a cyano group, a carboxylgroup, a nitrile group and a nitro group etc.

In the general formula [2], the substituent of the alkyl group oralkenyl group, which has a substituent, represented by R² includes, forexample, a halogen atom, a haloalkyl group, an alkoxy group, ahaloalkoxy group, a thioalkoxy group, an acyl group, a substituted aminogroup, a carboxyl group, a cyano group, a nitrile group and a nitrogroup etc.

The substituent of the aryl group, aralkyl group or heterocyclic group,which has a substituent, represented by R² includes, for example, ahalogen atom, an alkyl group, a haloalkyl group, an alkenyl group, analkoxy group, a haloalkoxy group, a thioalkoxy group, an acyl group, asubstituted amino group, a hydroxyl group, a cyano group, a carboxylgroup, a nitrile group and a nitro group etc.

The halogen atom as a substituent includes, for example, includes afluorine atom, a chlorine atom, a bromine atom and an iodine atom.

The haloalkyl group as a substituent includes any of a straight-chained,branched and cyclic group, and usually includes a group wherein a partor all of the hydrogen atoms in an alkyl group having of 1 to 18 carbonatoms, preferably 1 to 6 carbon atoms are substituted with a halogenatom (For example, a fluorine atom, a bromine atom, a chlorine atom andan iodine atom etc. are included and a fluorine atom is preferable amongthese.) and specifically, for example, a fluoromethyl group, achloromethyl group, a bromomethyl group, an iodomethyl group, atrifluoromethyl group, a trichloromethyl group, a tribromomethyl group,a 2-fluoroethyl group, a 2-chloroethyl group, a 2-bromoethyl group, apentaiodoethyl group, a pentachloroethyl group, a pentafluoroethylgroup, a pentabromoethyl group, a 3-fluoropropyl group, a 3-chloropropylgroup, a 3-bromopropyl group, a trifluoropropyl group, a trichloropropylgroup, a tribromopropyl group, a di(trifluoromethyl)methyl group, adi(trichloromethyl)methyl group, a di(tribromomethyl)methyl group, aheptafluoropropyl group, a heptachloropropyl group, a 4-fluorobutylgroup, a 4-chlorobutyl group, a 4-bromobutyl group, a nonafluorobutylgroup, a nonachlorobutyl group, a nonaburomobutyl group, a5-fluoropentyl group, a 5-chloropentyl group, a 5-bromopentyl group, a2,2,3,3,4,4,5,5-octafluoropentyl group (—CH₂(CF₂)₄H), a2,2,3,3,4,4,5,5-octachloropentyl group (—CH₂(CCl₂)₄H), a2,2,3,3,4,4,5,5-octabromopentyl group (—CH₂(CBr₂)₄H), a perfluoropentylgroup, a perchloropentyl group, a perbromopentyl group, a 6-fluorohexylgroup, a 6-chlorohexyl group, a 6-bromohexyl group, a perfluorohexylgroup, a perchlorohexyl group, a perbromohexyl group, a perfluoroheptylgroup, a perchloroheptyl group, a perbromoheptyl group, a perfluorooctylgroup, a perchlorooctyl group, a perbromooctyl group, a perfluorononylgroup, a perchlorononyl group, a perbromononyl group, a3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl group(—(CH₂)₂(CF₂)₇CF₃), a3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecachlorodecyl group(—(CH₂)₂(CCl₂)₇CBr₃), a3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecabromodecyl group(—(CH₂)₂(CBr₂)₇CBr₃), a perfluorodecyl group, a perchlorodecyl group, aperbromodecyl group, a perfluoroundecyl group, a perchloroundecyl group,a perbromoundecyl group, perfluorododecyl group, a perchlorododecylgroup, a perbromododecyl group, a perfluorotridecyl group, aperchlorotridecyl group, a perbromotridecyl group, a perfluorotetradecylgroup, a perchlorotetradecyl group, a perbromotetradecyl group, aperfluoropentadecyl group, a perchloropentadecyl group, aperbromopentadecyl group, a perfluorohexadecyl group, aperchlorohexadecyl group, a perbromohexadecyl group, aperfluoroheptadecyl group, a perchloroheptadecyl group, aperbromoheptadecyl group, a perfluorooctadecyl group, aperchlorooctadecyl group and a perbromooctadecyl group etc.

The alkoxy group as a substituent includes any of a straight-chained,branched and cyclic group, and usually includes a group having 1 to 18carbon atoms, preferably 1 to 8 carbon atoms and specifically, forexample, a methoxy group, an ethoxy group, a n-propoxy group, anisopropoxy group, a n-butoxy group, an isobutoxy group, a sec-butoxygroup, a tert-butoxy group, a n-pentyloxy group, an isopentyloxy group,a sec-pentyloxy group, a tert-pentyloxy group, a neopentyloxy group, an-hexyloxy group, an isohexyloxy group, a sec-hexyloxy group, atert-hexyloxy group, a neohexyloxy group, a n-heptyloxy group, anisoheptyloxy group, a sec-heptyloxy group, a tert-heptyloxy group, aneoheptyloxy group, a n-octyloxy group, an isooctyloxy group, asec-octyloxy group, a tert-octyloxy group, a neooctyloxy group, an-nonyloxy group, an isononyloxy group, a sec-nonyloxy group, atert-nonyloxy group, a neononyloxy group, a n-decyloxy group, anisodecyloxy group, a sec-decyloxy group, a tert-decyloxy group, aneodecyloxy group, a n-undecyloxy group, an isoundecyloxy group, asec-undecyloxy group, a tert-undecyloxy group, a neoundecyloxy group, an-dodecyloxy group, an isododecyloxy group, a sec-dodecyloxy group, atert-dodecyloxy group, a neododecyloxy group, a n-tridecyloxy group, anisotridecyloxy group, a sec-tridecyloxy group, a tert-tridecyloxy group,a neotridecyloxy group, a n-tetradecyloxy group, an isoteteradecyloxygroup, a sec-tetradecyloxy group, a tert-tetradecyloxy group, aneotetradecyloxy group, a n-pentadecyloxy group, an isopentadecyloxygroup, a sec-pentadecyloxy group, a tert-pentadecyloxy group, aneopentadecyloxy group, a n-hexadecyloxy group, an isohexadecyloxygroup, a sec-hexadecyloxy group, a tert-hexadecyloxy group, aneohexadecyloxy group, a n-heptadecyloxy group, an isoheptadecyloxygroup, a sec-heptadecyloxy group, a tert-heptadecyloxy group, aneoheptadecyloxy group, a n-octadecyloxy group, an isooctadecyloxygroup, a sec-octadecyloxy group, a tert-octadecyloxy group, anneooctadecyloxy group, a cyclopropoxy group, a cyclobutyloxy group, acyclopentyloxy group, a cyclohexyloxy group, a cycloheptyloxy group, acyclooctyloxy group, a cyclononyloxy group, a cyclodecyloxy group, acycloundecyloxy group, a cyclododecyloxy group, a cyclotridecyloxygroup, a cyclotetradecyloxy group, a cyclopentadecyloxy group, acyclohexadecyloxy group, a cycloheptadecyloxy group and acyclooctadecyloxy group etc.

The haloalkoxy group as a substituent includes any of astraight-chained, branched and cyclic group, and usually includes agroup wherein a part or all of the hydrogen atoms of an alkoxy group of1 to 18, preferably 1 to 8 carbon atoms are substituted with a halogenatom (For example, a fluorine atom, a bromine atom, a chlorine atom andan iodine atom are included and a fluorine atom is preferable amongthese.) and specifically, for example, a fluoromethoxy group, achloromethoxy group, a bromomethoxy group, an iodomethoxy group, atrifluoromethoxy group, a trichloromethoxy group, a tribromomethoxygroup, a 2-fluoroethoxy group, a 2-chloroethoxy group, a 2-bromoethoxygroup, a pentaiodoethoxy group, a pentachloroethoxy group, apentafluoroethoxy group, a pentabromoethoxy group, a 3-fluoropropoxygroup, a 3-chloropropoxy group, a 3-bromopropoxy group, atrifluoropropoxy group, a trichloropropoxy group, a tribromopropoxygroup, a di(trifluoromethyl)methoxy group, a di(trichloromethyl)methoxygroup, a di(tribromomethyl)methoxy group, a heptafluoropropoxy group, aheptachloropropoxy group, a 4-fluorobutoxy group, a 4-chlorobutoxygroup, a 4-bromobutoxy group, a nonafluorobutoxy group, anonachlorobutoxy group, a nonabromobutoxy group, a 5-fluoropentyloxygroup, a 5-chloropentyloxy group, a 5-bromopentyloxy group, aperfluoropentyloxy group, a perchloropentyloxy group, aperbromopentyloxy group, a 6-fluorohexyloxy group, a 6-chlorohexyloxygroup, a 6-bromohexyloxy group, a perfluorohexyloxy group, aperchlorohexyloxy group, a perbromohexyloxy group, a perfluoroheptyloxygroup, a perchloroheptyloxy group, a perbromoheptyloxy group, aperfluorooctyloxy group, a perchlorooctyloxy group, a perbromooctyloxygroup, a perfluorononyloxy group, a perchlorononyloxy group, aperbromononyloxy group, a perfluorodecyloxy group, a perchlorodecyloxygroup, a perbromodecyloxy group, a perfluoroundecyloxy group, aperchloroundecyloxy group, a perbromoundecyloxy group, aperfluorododecyloxy group, a perchlorododecyloxy group, aperbromododecyloxy group, a perfluorotridecyloxy group, aperchlorotridecyloxy group, a perbromotridecyloxy group, aperfluorotetradecyloxy group, a perchlorotetradecyloxy group, aperbromotetradecyloxy group, a perfluoropentadecyloxy group, aperchloropentadecyloxy group, a perbromopentadecyloxy group, aperfluorohexadecyloxy group, a perchlorohexadecyloxy group, aperbromohexadecyloxy group, a perfluoroheptadecyloxy group, aperchloroheptadecyloxy group, a perbromoheptadecyloxy group, aperfluorooctadecyloxy group, a perchlorooctadecyloxy group and aperbromooctadecyloxy group etc.

The thioalkoxy group as a substituent includes any of astraight-chained, branched and cyclic group, and usually includes agroup wherein the oxygen atom of an alkoxy group having 1 to 18 carbonatoms, preferably 1 to 8 carbon atoms is substituted with a sulfur atomand specifically, for example, a methylthio group, an ethylthio group, an-propylthio group, an isopropylthio group, a n-butylthio group, anisobutylthio group, a sec-butylthio group, a tert-butylthio group, an-pentylthio group, an isopentylthio group, a sec-pentylthio group, atert-pentylthio group, a neopentylthio group, a 1-methylpentylthiogroup, a n-hexylthio group, an isohexylthio group, a sec-hexylthiogroup, a tert-hexylthio group, a neohexylthio group, a n-heptylthiogroup, an isoheptylthio group, a sec-heptylthio group, a tert-heptylthiogroup, a neoheptylthio group, a n-octylthio group, an isooctylthiogroup, a sec-octylthio group, a tert-octylthio group, a neooctylthiogroup, a n-nonylthio group, an isononylthio group, a sec-nonylthiogroup, a tert-nonylthio group, a neononylthio group, a n-decylthiogroup, an isodecylthio group, a sec-decylthio group, a tert-decylthiogroup, a neodecylthio group, a n-undecylthio group, an isoundecylthiogroup, a sec-undecylthio group, a tert-undecylthio group, aneoundecylthio group, a n-dodecylthio group, an isododecylthio group, asec-dodecylthio group, a tert-dodecylthio group, a n-tridecylthio group,an isotridecylthio group, a sec-tridecylthio group, a tert-tridecylthiogroup, a neotridecylthio group, a n-tetradecylthio group, anisoteteradecylthio group, a sec-tetradecylthio group, atert-tetradecylthio group, a neotetradecylthio group, a n-pentadecylthiogroup, an isopentadecylthio group, a sec-pentadecylthio group, atert-pentadecylthio group, a neopentadecylthio group, a n-hexadecylthiogroup, an isohexadecylthio group, a sec-hexadecylthio group, atert-hexadecylthio group, a neohexadecylthio group, n-heptadecylthiogroup, an isoheptadecylthio group, a sec-heptadecylthio group, atert-heptadecylthio group, a neoheptadecylthio group, a n-octadecylthiogroup, an isooctadecylthio group, a sec-octadecylthio group, atert-octadecylthio group, a neooctadecylthio group, a cyclopropylthiogroup, a cyclobutylthio group, a cyclopentylthio group, a cyclohexylthiogroup, a cycloheptylthio group, a cyclooctylthio group, a cyclononylthiogroup, a cyclodecylthio group, a cycloundecylthio group, acyclododecylthio group, a cyclotridecylthio group, a cyclotetradecylthiogroup, a cyclopentadecylthio group, a cyclohexadecylthio group, acycloheptadecylthio group and a cyclooctadecylthio group etc.

The acyl group as a substituent usually includes a group derived from acarboxylic acid having 1 to 20 carbon atoms and specifically, forexample, a group derived from an aliphatic carboxylic acid such as, forexample, a formyl group, an acetyl group, a propionyl group, a butyrylgroup, an isobutyryl group, a valeryl group, an isovaleryl group, apivaloyl group, a hexanoyl group, a heptanoyl group, an octanoyl group,a nonanoyl group, a decanoyl group, a dodecanoyl group, a tridecanoylgroup, a tetradecanoyl group, a pentadecanoyl group, a hexadecanoylgroup, a heptadecanoyl group, an octadecanoyl group, a nonadecanoylgroup and an icosanoyl group, and for example, a group derived from anaromatic carboxylic acid such as, for example, a benzoyl group and anaphthoyl group etc.

The substituted amino group as a substituent includes a group wherein 2hydrogen atoms in an amino group are substituted with, for example, analkyl group having 1 to 6 carbon atoms or an aryl group etc.

The alkyl group of 1 to 10 carbon atoms as a substituent of thesubstituted amino group includes any of a straight-chained, branched andcyclic group and specifically, for example, a methyl group, an ethylgroup, a n-propyl group, an isopropyl group, a n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, a n-pentyl group,an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentylgroup, a 1-methylpentyl group, a n-hexyl group, an isohexyl group, asec-hexyl group, a tert-hexyl group, a neohexyl group, a n-heptyl group,an isoheptyl group, a sec-heptyl group, a tert-heptyl group, a neoheptylgroup, a n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, a neooctyl group, a n-nonyl group, an isononyl group,a sec-nonyl group, a tert-nonyl group, a neononyl group, a n-decylgroup, an isodecyl group, a sec-decyl group, a tert-decyl group, aneodecyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentylgroup, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, acyclononyl group, a cyclodecyl group and an adamantyl group etc.

The aryl group as a substituent of the substituted amino group usuallyincludes a group having 6 to 14 carbon atoms, preferably 6 to 10 carbonatoms and specifically, for example, a phenyl group, a naphthyl group, aphenanthryl group and an anthryl group etc.

The alkyl group as a substituent includes any of a straight-chained,branched and cyclic group, and usually includes a group of 1 to 18carbon atoms and specifically, for example, a methyl group, an ethylgroup, a n-propyl group, an isopropyl group, a n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, a n-pentyl group,an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentylgroup, a 1-methylpentyl group, a n-hexyl group, an isohexyl group, asec-hexyl group, a tert-hexyl group, a neohexyl group, a n-heptyl group,an isoheptyl group, a sec-heptyl group, a tert-heptyl group, a neoheptylgroup, a n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, a neooctyl group, a n-nonyl group, an isononyl group,a sec-nonyl group, a tert-nonyl group, a neononyl group, a n-decylgroup, an isodecyl group, a sec-decyl group, a tert-decyl group, aneodecyl group, a n-undecyl group, an isoundecyl group, a sec-undecylgroup, a tert-undecyl group, a neoundecyl group, a n-dodecyl group, anisododecyl group, a sec-dodecyl group, a tert-dodecyl group, an-tridecyl group, an isotridecyl group, a sec-tridecyl group, atert-tridecyl group, a neotridecyl group, a n-tetradecyl group, anisotetradecyl group, a sec-tetradecyl group, a tert-tetradecyl group, aneotetradecyl group, a n-pentadecyl group, an isopentadecyl group, asec-pentadecyl group, a tert-pentadecyl group, a neopentadecyl group, an-hexadecyl group, an isohexadecyl group, a sec-hexadecyl group, atert-hexadecyl group, a neohexadecyl group, a n-heptadecyl group, anisoheptadecyl group, a sec-heptadecyl group, a tert-heptadecyl group, aneoheptadecyl group, a n-octadecyl group, an isooctadecyl group, asec-octadecyl group, a tert-octadecyl group, a neooctadecyl group, acyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, acyclodecyl group, a cycloundecyl group, a cyclododecyl group, acyclotridecyl group, a cyclotetradecyl group, a cyclopentadecyl group, acyclohexadecyl group, a cycloheptadecyl group and a cyclooctadecyl groupetc.

The alkenyl group as a substituent includes any of a straight-chained,branched and cyclic group, and usually includes a group having 2 to 12carbon atoms, preferably 2 to 8 carbon atoms and specifically, forexample, a vinyl group, an allyl group, a 1-propenyl group, anisopropenyl group, a 1-butenyl group, a 2-butenyl group, a 3-butenylgroup, a 2-methylallyl group, a 1-pentenyl group, a 2-pentenyl group, a3-pentenyl group, a 4-pentenyl group, a 2-methyl-2-butenyl group, a1-hexenyl group, a 2-hexenyl group, a 3-hexenyl group, a 5-hexenylgroup, a 2-methyl-2-pentenyl group, a 1-heptenyl group, a 2-heptenylgroup, a 3-heptenyl group, a 4-heptenyl group, a 5-heptenyl group, a6-heptenyl group, a 1-octenyl group, a 2-octenyl group, a 3-octenylgroup, a 4-octenyl group, a 1-nonenyl group, a 2-nonenyl group, a3-nonenyl group, a 4-nonenyl group, a 1-decenyl group, a 2-decenylgroup, a 3-decenyl group,a 4-decenyl group, a 5-decenyl group, a1-undecenyl group, a 2-undecenyl group, a 3-undecenyl group, a4-undecenyl group, a 5-undecenyl group, a 1-dodecenyl group, a2-dodecenyl group, a 3-dodecenyl group, a 4-dodecenyl group, a5-dodecenyl group, a 6-dodecenyl group, a 1-cyclobutenyl group, a1-cyclopentenyl group and a 1-cyclohexenyl group etc.

In the general formula [7], the alkylene chain of an alkylene chainwhich may have a substituent represents a straight-chained alkylenegroup having usually 2 to 8 carbon atoms, preferably 3 to 6 carbon atomsand includes specifically, for example, an ethylene group, atrimethylene group, a tetramethylene group, a pentamethylene group, ahexamethylene group, a heptamethylene group and an octamethylene groupetc.

The substituent of an alkylene chain which may have a substituent is notparticularly limited as long as it has no adverse effect on the estercondensation reaction and includes, for example, the similar one to theexemplification of the substituent of the alkyl group, alkenyl group oralkinyl group which has a substituent represented by R¹ in the generalformula [1].

In the general formula [9], the alkylene chain of 1 to 4 carbon atomsrepresented by Ti usually includes a straight-chained alkylene grouphaving 1 to 4 carbon atoms, preferably 2 to 3 carbon atoms andspecifically, for example, a methylene group, an ethylene group, atrimethylene group and a tetramethylene group etc.

In the general formula [11], the alkylene group of an alkylene group of1 to 8 carbon atoms which may have a substituent represented by T₂includes a straight-chained or branched, and usually includes a grouphaving 1 to 8 carbon atoms and specifically, for example, a methylenegroup, an ethylene group, a trimethylene group, a propylene group, atetramethylene group, a butylene group, a 2-methylpropylene group, apentamethylene group, a pentylene group, a 2-methyltetramethylene group,a 2,2-dimethyltrimethylene group, a 2-ethyltrimethylene group, ahexamethylene group, a hexylene group, a 2-methylpentamethylene group, a3-methylpentamethylene group, a heptamethylene group, a heptylene group,an octylene group and a 2-ethylhexylene group etc.

The arylene group of an arylene group which may have a substituentrepresented by T₂ usually includes a group having 6 to 10 carbon atomsand specifically, for example, an o-phenylene group, a m-phenylenegroup, a p-phenylene group, a 1,5-naphthylene group, a 1,8-naphthylenegroup, a 2,7-naphthylene group and a 2,6-naphthylene group etc.

The substituent of an alkylene group having 1 to 8 carbon atoms or anarylene group, which may have a substituent, represented by T₂ is notparticularly limited as long as it has no adverse effect on the estercondensation reaction and includes, for example, the similar one to theexemplification of the substituent of the alkyl group, alkenyl group oralkinyl group, which has a substituent, represented by R¹ in the generalformula [1].

The corresponding ester compound obtained by the method of the presentinvention, that is, the condensation reaction of an alcohol and acarboxylic acid includes, for example, the following compounds,

That is, (i) a compound represented by the general formula [3]:

R¹—OCO—R²   [3]

(wherein R¹ and R² are the same as the above) that is obtained byreacting 1 equivalent of an alcohol represented by the general formula[1] and 1 equivalent of a carboxylic acid represented by the generalformula [2];

(ii) a compound represented by the general formula [8]:

(wherein T is the same as the above) that is obtained from a compoundrepresented by the general formula [7] wherein an alcohol and acarboxylic acid are the same compound;

(iii) a compound represented by the general formula [10]:

R²—COO-(T₁-O)_(n)—OC—R²   [10]

(wherein R², T₁ and n are the same as the above) that is obtained byreacting 1 equivalent of a dialcohol represented by the general formula[9] and 2 equivalents of a carboxylic acid represented by the generalformula [2];and

(iv) a compound represented by the general formula [12]:

R¹—OCO-T₂-COO—R¹   [12]

(wherein R¹ and T₂ are the same as the above) that is obtained byreacting 2 equivalents of an alcohol represented by the general formula[1] and 1 equivalent of a dicarboxylic acid represented by the generalformula [11].

The preferable specific example of alcohols represented by the generalformula [1] includes saturated aliphatic alcohols such as, for example,methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol,2-methyl-1-propanol, 2-methyl-2-propanol, tert-butanol, n-pentanol,tert-amyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol,3-methyl-2-butanol, neopentyl alcohol, 2-pentanol, 3-pentanol,2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol,2-ethyl-1-butanol, n-hexanol, 2-hexanol, 3-hexanol, cyclohexanol,2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol,3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol,4-methyl-1-pentanol, 4-methyl-2-pentanol, 2,2-dimethyl-3-pentanol,2,3-dimethyl-3-pentanol, 2,4-dimethyl-3-pentanol,4,4-dimethyl-2-pentanol, 3-ethyl-3-pentanol, n-heptanol, 2-heptanol,3-heptanol, 2-methyl-2-hexanol, 2-methyl-3-hexanol, 5-methyl-1-hexanol,5-methyl-2-hexanol, 1-cyclohexyl ethanol, 2-cyclohexyl ethanol,n-octanol, 2-ethylhexyl alcohol, 3-cyclopentyl-1-propanol,2,3-dimethylcyclohexanol, 2,6-dimethylcyclohexanol,3,5-dimethylcyclohexanol, 2-ethylcyclohexanol, 4-ethylcyclohexanol,6-methyl-5-heptene-2-ol, 1-octene-3-ol, 2,2-dimethyl-4-heptanol,3-ethyl-2,2-dimethyl-3-pentanol, 3-methyl-3-octanol, cyclooctanol,n-nonanol, 2-nonanol, 3,5,5-trimethyl-1-hexanol, 2-decanol, n-decanol,4-decanol, decyl alcohol, 3, 7-dimethyl-1-octanol, 3,7-dimethyl-3-octanol, n-undecanol, 2-undecanol, 2-butyl-1-octanol,n-dodecanol, 2-dodecanol, lauryl alcohol and stearyl alcohol; alicyclicalcohols such as, for example, menthol, borneol, cyclohexanol,cyclopentanol and cycloheptanol; halogen-substituted aliphatic alcoholssuch as, for example, perfluoroethanol, 2-fluoroethanol,2,2-difluoroethanol, 2,2,2-trifluoroethanol, pentafluoroethanol,1-chloroethanol, 2,2-dichloroethanol, 2,2,2-trichloroethanol,2-bromoethanol, 2,2,2-tribromoethanol, 2-iodoethanol, and3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctane-1-ol; formyl-substitutedaliphatic alcohols such as, for example, 5-hydroxyhexanol;carboxy-substituted aliphatic alcohols such as, for example,3-hydroxy-1-cyclohexane carboxylic acid; aromatic alcohols such as, forexample, phenol, cresol, 2,3-xylenol, carvacrol, thymol, naphthol,anthrol, phenanthrol and 1-chrysenol; aromatic aliphatic alcohols suchas, for example, benzyl alcohol, phenethyl alcohol, triphenylmethanoland 2-naphthalene ethanol; aralkyl alcohols such as, for example, allylalcohol, geraniol, phytol, 2-ethyl-2-buten-1-ol and 2-cyclohexene-1-ol;unsaturated aliphatic alcohols such as, for example, alkenyl alcoholsincluding, for example, propargyl alcohol; heterocycle-substitutedalcohols such as, for example, 8-quinolinol, indole-5-ol,3-hydroxythiophene, 1-hydroxypiperidine and furfuryl alcohol; and, forexample, ethylene glycol monomethyl ether, diethylene glycol monomethylether, triethylene glycol monomethyl ether, tetraethylene glycolmonomethyl ether, pentaethylene glycol monomethyl ether and hexaethyleneglycol monomethyl ether etc.

The preferable specific example of dialcohols represented by the generalformula [9] includes, for example, ethylene glycol, diethylene glycol,triethylene glycol, tetraethylene glycol, pentaethylene glycol andhexaethylene glycol etc.

The preferable specific example of carboxylic acids represented by thegeneral formula [2] includes saturated aliphatic carboxylic acids suchas, for example, for example, formic acid, acetic acid, propionic acid,butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalicacid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid,decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristicacid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearicacid, nonadecanoic acid, icosanoic acid, henicosanoic acid, docosanoicacid and tricosanoic acid; halogenated saturated aliphatic carboxylicacids such as, for example, fluoroacetic acid, chloroacetic acid,bromoacetic acid, iodoacetic acid, difluoroacetic acid, dichloroaceticacid, dibromoacetic acid, diiodoacetic acid, trifluoroacetic acid,trichloroacetic acid, tribromoacetic acid, triiodoacetic acid,2-fluoropropionic acid, 2-chloropropionic acid, 2-bromopropionic acid,2-iodopropionic acid, trifluoropropionic acid, trichloropropionic acid,pentafluoropropionic acid, pentachloropropionic acid,pentabromopropionic acid, pentaiodopropionic acid,2,2-bis(trifluoromethyl)propionic acid,2,2-bis(trichloromethyl)propionic acid, 2,2-bis(tribromomethyl)propionicacid, 2,2-bis(triiodomethyl)propionic acid, trifluorobutyric acid,trichlorobutyric acid, pentafluorobutyric acid, heptachlorobutyric acid,heptafluorobutyric acid, heptabromobutyric acid, heptaiodobutyric acid,heptafluoroisobutyric acid, heptachloroisobutyric acid,heptabromoisobutyric acid, heptaiodoisobutyric acid, trifluorovalericacid, 5H -perfluorovaleric acid, 5H-perchlorovaleric acid,5H-perbromovaleric acid, 5H-periodovaleric acid, nonafluorovaleric acid,nonachlorovaleric acid, nonabromovaleric acid, nonaiodovaleric acid,trifluorohexanoic acid, trichlorohexanoic acid, perfluorohexanoic acid,perchlorohexanoic acid, perbromohexanoic acid, periodohexanoic acid,7-chlorododecafluoroheptanoic acid, 7-chlorododecachloroheptanoic acid,7-chlorododecabromoheptanoic acid, 7-chlorododecaiodoheptanoic acid,trifluoroheptanoic acid, trichloroheptanoic acid, 7H-perfluoroheptanoicacid, 7H-perchloroheptanoic acid, 7H-perbromoheptanoic acid,7H-periodoheptanoic acid, trifluorooctanoic acid, trichlorooctanoicacid, pentadecafluorooctanoic acid, pentadecachlorooctanoic acid,pentadecabromooctanoic acid, pentadecaiodooctanoic acid,trifluorononanoic acid, trichlorononanoic acid,9H-hexadecafluorononanoic acid, 9H-hexadecachlorononanoic acid,9H-hexadecabromononanoic acid, 9H-hexadecaiodononanoic acid,perfluorononanoic acid, perchlorononanoic acid, perbromononanoic acid,periodononanoic acid, trifluorodecanoic acid, trichlorodecanoic acid,nonadecafluorodecanoic acid, nonadecachlorodecanoic acid,nonadecabromodecanoic acid, nonadecaiododecanoic acid,trifluoroundecanoic acid, trichloroundecanoic acid, perfluoroundecanoicacid, perchloroundecanoic acid, perbromoundecanoic acid,periodoundecanoic acid, trifluorododecanoic acid, trichlorododecanoicacid, perfluorododecanoic acid, perchlorododecanoic acid,perbromododecanoic acid, periodododecanoic acid, trifluorotridecanoicacid, trichlorotridecanoic acid, perfluorotridecanoic acid,perchlorotridecanoic acid, perbromotridecanoic acid, periodotridecanoicacid, trifluorotetradecanoic acid, trichlorotetradecanoic acid,perfluorotetradecanoic acid, perchlorotetradecanoic acid,perbromotetradecanoic acid, periodotetradecanoic acid,trifluoropentadecanoic acid, trichloropentadecanoic acid,perfluoropentadecanoic acid, perchloropentadecanoic acid,perbromopentadecanoic acid, periodopentadecanoic acid,perfluorohexadecanoic acid, perchlorohexadecanoic acid,perbromohexadecanoic acid, periodohexadecanoic acid,perfluoroheptadecanoic acid, perchloroheptadecanoic acid,perbromoheptadecanoic acid, periodoheptadecanoic acid,perfluorooctadecanoic acid, perchlorooctadecanoic acid,perbromooctadecanoic acid, periodoctadecanoic acid,perfluorononadecanoic acid, perchlorononadecanoic acid,perbromononadecanoic acid, periodononadecanoic acid, perfluoroicosanoicacid, perchloroicosanoic acid, perbromoicosanoic acid, periodoicosanoicacid, perfluorohenicosanoic acid, perchlorohenicosanoic acid,perbromohenicosanoic acid, periodohenicosanoic acid, perfluorodocosanoicacid, perchlorodocosanoic acid, perbromodocosanoic acid,periododocosanoic acid, perfluorotricosanoic acid, perchlorotricosanoicacid, perbromotricosanoic acid and periodotricosanoic acid; alicycliccarboxylic acids such as, for example, cyclohexanecarboxylic acid,camphoric acid, adamantane carboxylic acid; halogenated alicycliccarboxylic acids such as, for example, 4-fluorocyclohexanecarboxylicacid, 4-chlorocyclohexanecarboxylic acid, 4-bromocyclohexanecarboxylicacid, 4-iodocyclohexanecarboxylic acid, pentafluorocyclohexanecarboxylicacid, pentachlorocyclohexanecarboxylic acid,pentabromocyclohexanecarboxylic acid, pentaiodocyclohexanecarboxylicacid, 4-(trifluoromethyl)cyclohexanecarboxylic acid,4-(trichloromethyl)cyclohexanecarboxylic acid,4-(tribromomethyl)cyclohexanecarboxylic acid and4-(triiodomethyl)cyclohexanecarboxylic acid; alkylthioaliphaticcarboxylic acids such as, for example, methylthioacetic acid,ethylthioacetic acid, propylthioacetic acid, isopropylthioacetic acid,butylthioacetic acid, isobutylthioacetic acid, t-butylthioacetic acidand 3-methylthiopropionic acid; alkoxyaliphatic carboxylic acids suchas, for example, methoxyacetic acid, ethoxyacetic acid, propoxyaceticacid, isopropoxyacetic acid, butoxyacetic acid, isobutoxyacetic acid,3-methoxypropionic acid and 3-methoxybutyric acid; aromatic carboxylicacids such as, for example, benzoic acid, naphthoic acid,anthracenecarboxylic acid, pyrenecarboxylic acid, pyrilenecarboxylicacid and pentaphenecarboxylic acid; halogenated aromatic carboxylicacids such as, for example, fluorobenzoic acid, chlorobenzoic acid,bromobenzoic acid, iodobenzoic acid, difluorobenzoic acid,dichlorobenzoic acid, dibromobenzoic acid, diiodobenzoic acid,trifluorobenzoic acid, trichlorobenzoic acid, tribromobenzoic acid,triiodobenzoic acid, tetrafluorobenzoic acid, tetrachlorobenzoic acid,tetrabromobenzoic acid, tetraiodobenzoic acid, pentafluorobenzoic acid,pentachlorobenzoic acid, pentabromobenzoic acid, pentaiodobenzoic acid,fluoronaphthoic acid, chloronaphthoic acid, bromonaphthoic acid,iodonaphthoic acid, perfluoronaphthoic acid, perchloronaphthoic acid,perbromonaphthoic acid, periodonaphthoic acid,fluoroanthracenecarboxylic acid, chloroanthracenecarboxylic acid,bromoanthracenecarboxylic acid, iodoanthracenecarboxylic acid,perfluoroanthracenecarboxylic acid, perchloroanthracenecarboxylic acid,perbromoanthracenecarboxylic acid and periodoanthracenecarboxylic acid;alkyl substituted aromatic carboxylic acids such as, for example, toluicacid (p-tolylacetic acid) and 2,4,6-tri(isopropyl)benzoic acid;haloalkyl substituted aromatic carboxylic acids such as, for example,2-trifluoromethylbenzoic acid, 2-trichloromethylbenzoic acid,2-tribromomethylbenzoic acid, 2-triiodomethylbenzoic acid,3-trifluoromethylbenzoic acid, 3-trichloromethylbenzoic acid,3-tribromomethylbenzoic acid, 3-triiodomethylbenzoic acid,4-trifluoromethylbenzoic acid, 4-trichloromethylbenzoic acid,4-tribromomethylbenzoic acid, 4-triiodomethylbenzoic acid,2-fluoro-4-(trifluoromethyl)benzoic acid,2-chloro-4-(trichloromethyl)benzoic acid,2-bromo-4-(tribromomethyl)benzoic acid,2,3,4-trifluoro-6-(trifluoromethyl)benzoic acid,2,3,4-trichloro-6-(trichloromethyl)benzoic acid,2,3,4-tribromo-6-(tribromomethyl)benzoic acid,2,3,4-triiodo-6-(triiodomethyl)benzoic acid,2-iodo-4-(triiodomethyl)benzoic acid, 2,4-bis(trifluoromethyl)benzoicacid, 2,4-bis(trichloromethyl)benzoic acid,2,4-bis(tribromomethyl)benzoic acid, 2,4-bis(triiodomethyl)benzoic acid,2,6-bis(trifluoromethyl)benzoic acid, 2,6-bis(trichloromethyl)benzoicacid, 2,6-bis(tribromomethyl)benzoic acid, 2,6-bis(triiodomethyl)benzoicacid, 3,5-bis(trifluoromethyl)benzoic acid,3,5-bis(trichloromethyl)benzoic acid, 3,5-bis(tribromomethyl)benzoicacid, 3,5-bis(triiodomethyl)benzoic acid,2,4,6-tris(trifluoromethyl)benzoic acid,2,4,6-tris(trichloromethyl)benzoic acid,2,4,6-tris(tribromomethyl)benzoic acid, 2,4,6-tris(triiodomethyl)benzoicacid, 2-chloro-6-fluoro-3-methylbenzoic acid, trifluoromethylnaphthoicacid, trichloromethylnaphthoic acid, tribromomethylnaphthoic acid,triiodomethylnaphthoic acid, bis(trifluoromethyl)naphthoic acid,bis(trichloromethyl)naphthoic acid, bis(tribromomethyl)naphthoic acid,bis(triiodomethyl)naphthoic acid, tris(trifluoromethyl)naphthoic acid,tris(trichloromethyl)naphthoic acid, tris(tribromomethyl)naphthoic acid,tris(triiodomethyl)naphthoic acid, trifluoromethylanthracenecarboxylicacid, trichloromethylanthracenecarboxylic acid,tribromomethylanthracenecarboxylic acid andtriiodomethylanthracenecarboxylic acid; haloalkoxy substituted aromaticcarboxylic acids such as, for example, 4-trifluoromethoxybenzoic acid,4-trichloromethoxybenzoic acid, 4-tribromomethoxybenzoic acid,4-triiodomethoxybenzoic acid, 4-pentafluoroethoxybenzoic acid,4-pentachloroethoxybenzoic acid, 4-pentabromoethoxybenzoic acid,4-pentaiodoethoxybenzoic acid, 3,4-bis(trifluoromethoxy)benzoic acid,3,4-bis(trichloromethoxy)benzoic acid, 3,4-bis(tribromomethoxy)benzoicacid, 3,4-bis(triiodomethoxy)benzoic acid,2,5-bis(2,2,2-trifluoroethoxy)benzoic acid,2,5-bis(2,2,2-trichloroethoxy)benzoic acid,2,5-bis(2,2,2-tribromoethoxy)benzoic acid and2,5-bis(2,2,2-triiodoethoxy)benzoic acid; nitro substituted aromaticcarboxylic acids such as, for example, trinitrobenzoic acid; aromaticaliphatic carboxylic acids such as, for example, α-toluic acid,hydrocinnamic acid, hydroatropic acid, 3-phenylpropionic acid,4-phenylbutyric acid, 5-phenylpentanoic acid, 6-phenylhexanoic acid,7-phenylheptanoic acid and 6-(2-naphthyl)hexanoic acid; oxocarboxylicacids such as, for example, 2-formylacetic acid, acetoacetic acid,3-benzoylpropionic acid, 4-formylbutyric acid, 3-oxovaleric acid,5-oxovaleric acid, 3,5-dioxovaleric acid, 6-formylhexanecarboxylic acid,2-oxo-1-cyclohexanecarboxylic acid, 4-(2-oxobutyl)benzoic acid,p-(3-formylpropyl)benzoic acid, 4-formylphenylacetic acid,β-oxocyclohexanepropionic acid and pyruvic acid; heterocyclic carboxylicacids such as, for example, 2-furancarboxylic acid; ethylenicallyunsaturated carboxylic acids having 3 to 20 carbon atoms such as, forexample, acrylic acid, methacrylic acid, vinylacetic acid, allylaceticacid and vinylbenzoic acid; ethylenically unsaturated carboxylic esterssuch as, for example, methyl methacrylate, ethyl methacrylate, propylmethacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, methylacrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexylacrylate, lauryl methacrylate and stearyl acrylate(These acids may be asalt such as, for example, a salt of an alkaline metal such as, forexample, sodium and potassium, and an ammonium salt.)

The preferable specific example of dicarboxylic acids represented by thegeneral formula [11] includes aliphatic dicarboxylic acids such as, forexample, malonic acid, succinic acid, glutaric acid and adipic acid;aromatic dicarboxylic acids such as, for example, phthalic acid,isophthalic acid and terephthalic acid etc.

The preferable specific example of compounds represented by the generalformula [7] includes, for example, 2-hydroxyacetic acid,3-hydroxypropionic acid, 4-hydroxybutanoic acid, 5-hydroxypentanoic acidand 6-hydroxycaproic acid etc.

The typical specific example of compounds represented by the generalformula [3] includes, for example,3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctane 2-methyl-2-propenateester, ethyl methylthioacetate, ethyl methoxyacetate, ethylp-tolylacetate, ethyl 2-furancarboxylate, ethyl 5-chlorovalerate, ethylacetylacetate, butyl acetate and phenyl acetate.

The typical specific example of compounds represented by the generalformula [8] includes, for example, 3-oxiranone, 2-oxetanone,dihydro-2-furanone, tetrahidro-2H-pyrane-2-one and ε-caprolactone.

The typical specific example of compounds represented by the generalformula [10] includes, for example, 1,2-ethanediyl dimethyl ester,3-oxo-2,4,7,10-tetraoxa-11-undecanoic acid methyl ester,2,5,8,11-tetraoxadodecan dicarboxylic acid dimethyl ester and2,5,8,11,14-pentaoxapentadodecanoic dicarboxylic acid dimethyl ester.

The typical specific example of compounds represented by the generalformula [12] includes, for example, butane dicarboxylic acid dimethylester, pentane dicarboxylic acid dimethyl ester, hexane dicarboxylicacid dimethyl ester and benzen dicarboxylic acid dimethyl ester.

The involatile acid catalyst includes a solid or a liquid under ordinarytemperature and pressure and specifically, for example, sulfuric acidand a sulfonic acid represented by the general formula [4]:

R³—SO₃H   [4]

(wherein R³ represents an alkyl group, an aryl group or an aralkylgroup, which may have a substituent).

In the general formula [4], the alkyl group of an alkyl group which mayhave a substituent represented by R³ includes any of a straight-chained,branched and cyclic group, and usually includes a group having 1 to 18carbon atoms, preferably 1 to 4 carbon atoms and specifically, forexample, a methyl group, an ethyl group, a n-propyl group, an isopropylgroup, a n-butyl group, an isobutyl group, a sec-butyl group, atert-butyl group, a n-pentyl group, an isopentyl group, a sec-pentylgroup, a tert-pentyl group, a neopentyl group, a 1-methylpentyl group, an-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group,a neohexyl group, a n-heptyl group, an isoheptyl group, a sec-heptylgroup, a tert-heptyl group, a neoheptyl group, a n-octyl group, anisooctyl group, a sec-octyl group, a tert-octyl group, a neooctyl group,a n-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonylgroup, a neononyl group, a n-decyl group, an isodecyl group, a sec-decylgroup, a tert-decyl group, a neodecyl group, a n-undecyl group, anisoundecyl group, a sec-undecyl group, a tert-undecyl group, aneoundecyl group, a n-dodecyl group, an isododecyl group, a sec-dodecylgroup, a tert-dodecyl group, a n-tridecyl group, an isotridecyl group, asec-tridecyl group, a tert-tridecyl group, a neotridecyl group, an-tetradecyl group, an isotetradecyl group, a sec-tetradecyl group, atert-tetradecyl group, a neotetradecyl group, a n-pentadecyl group, anisopentadecyl group, a sec-pentadecyl group, a tert-pentadecyl group, aneopentadecyl group, a n-hexadecyl group, an isohexadecyl group, asec-hexadecyl group, a tert-hexadecyl group, a neohexadecyl group, an-heptadecyl group, an isoheptadecyl group, a sec-heptadecyl group, atert-heptadecyl group, a neoheptadecyl group, a n-octadecyl group, anisooctadecyl group, a sec-octadecyl group, a tert-octadecyl group, aneooctadecyl group, a cyclopropyl group, a cyclobutyl group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctylgroup, a cyclononyl group, a cyclodecyl group, a cycloundecyl group, acyclododecyl group, a cyclotridecyl group, a cyclotetradecyl group, acyclopentadecyl group, a cyclohexadecyl group, a cycloheptadecyl groupand a cyclooctadecyl group etc.

The aryl group of an aryl group which may have a substituent representedby R³ usually includes a group having 6 to 15 carbon atoms andspecifically, for example, a phenyl group, a naphthyl group and ananthryl group etc.

The aralkyl group of an aralkyl group which may have a substituentrepresented by R³ usually includes a group having 7 to 15 carbon atomsand specifically, for example, a benzyl group, a phenethyl group, aphenylpropyl group and a naphthylmethyl group etc.

The substitute of an alkyl group, an aryl group or an aralkyl group.which has a substituent, represented by R³ includes, for example, ahalogen atom, an alkyl group and a haloalkyl group etc.

The halogen atom as a substitute includes, for example, a fluorine atom,a chlorine atom, a bromine atom and an iodine atom etc.

The alkyl group as a substitute includes any of a straight-chained,branched and cyclic group, and usually includes a group having 1 to 12carbon atoms and specifically, for example, a methyl group, an ethylgroup, a n-propyl group, an isopropyl group, a n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, a n-pentyl group,an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentylgroup, a 1-methylpentyl group, a n-hexyl group, an isohexyl group, asec-hexyl group, a tert-hexyl group, a neohexyl group, a n-heptyl group,an isoheptyl group, a sec-heptyl group, a tert-heptyl group, a neoheptylgroup, a n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, a neooctyl group, a n-nonyl group, an isononyl group,a sec-nonyl group, a tert-nonyl group, a neononyl group, a n-decylgroup, an isodecyl group, a sec-decyl group, a tert-decyl group, aneodecyl group, a n-undecyl group, an isoundecyl group, a sec-undecylgroup, a tert-undecyl group, a neoundecyl group, a n-dodecyl group, anisododecyl group, a sec-dodecyl group, a tert-dodecyl group, acyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, acyclodecyl group, a cycloundecyl group and a cyclododecyl group etc.

The haloalkyl group as a substituent includes any of a straight-chained,branched and cyclic group, and usually includes a group wherein a partor all of the hydrogen atoms of an alkyl group having 1 to 18 carbonatoms, preferably 1 to 6 carbon atoms are substituted with a halogenatom (For example, a fluorine atom, a bromine atom, a chlorine atom andan iodine atom etc. are included and a fluorine atom is preferable amongthese.) and specifically, for example, a fluoromethyl group, achloromethyl group, a bromomethyl group, an iodomethyl group, atrifluoromethyl group, a trichloromethyl group, a tribromomethyl group,a 2-fluoroethyl group, a 2-chloroethyl group, a 2-bromoethyl group, apentaiodoethyl group, a pentachloroethyl group, a pentafluoroethylgroup, a pentabromoethyl group, a 3-fluoropropyl group, a 3-chloropropylgroup, a 3-bromopropyl group, a trifluoropropyl group, a trichloropropylgroup, a tribromopropyl group, a di(trifluoromethyl)methyl group, adi(trichloromethyl)methyl group, a di(tribromomethyl)methyl group, aheptafluoropropyl group, a heptachloropropyl group, a 4-fluorobutylgroup, a 4-chlorobutyl group, a 4-bromobutyl group, a nonafluorobutylgroup, a nonachlorobutyl group, a nonaburomobutyl group, a5-fluoropentyl group, a 5-chloropentyl group, a 5-bromopentyl group, a2,2,3,3,4,4,5,5-octafluoropentyl group (—CH₂(CF₂)₄H), a2,2,3,3,4,4,5,5-octachloropentyl group (—CH₂(CCl₂)₄H), a2,2,3,3,4,4,5,5-octabromopentyl group (—CH₂(CBr₂)₄H), a perfluoropentylgroup, a perchloropentyl group, a perbromopentyl group, a 6-fluorohexylgroup, a 6-chlorohexyl group, a 6-bromohexyl group, a perfluorohexylgroup, a perchlorohexyl group, a perbromohexyl group, a perfluoroheptylgroup, a perchloroheptyl group, a perbromoheptyl group, a perfluorooctylgroup, a perchlorooctyl group, a perbromooctyl group, a perfluorononylgroup, a perchlorononyl group, a perbromononyl group, a3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl group(—(CH₂)₂(CF₂)₇CF3), a3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecachlorodecyl group(—(CH₂)₂(CCl₂)₇CCl₃), a3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecabromodecyl group(—(CH₂)₂(CBr₂)₇CBr₃), a perfluorodecyl group, a perchlorodecyl group, aperbromodecyl group, a perfluoroundecyl group, a perchloroundecyl group,a perbromoundecyl group, a perfluorododecyl group, a perchlorododecylgroup, a perbromododecyl group, a perfluorotridecyl group, aperchlorotridecyl group, a perbromotridecyl group, a perfluorotetradecylgroup, a perchlorotetradecyl group, aperbromotetradecyl group, aperfluoropentadecyl group, a perchloropentadecyl group, aperbromopentadecyl group, a perfluorohexadecyl group, aperchlorohexadecyl group, a perbromohexadecyl group, aperfluoroheptadecyl group, a perchloroheptadecyl group, aperbromoheptadecyl group, a perfluorooctadecyl group, aperchlorooctadecyl group and a perbromooctadecyl group etc.

The preferable specific example of sulfonic acids represented by thegeneral formula [4] includes alkylsulfonic acids such as, for example, amethanesulfonic acid, ethanesulfonic acid, propanesulfonic acid,butanesulfonic acid, pentanesulfonic acid, hexanesulfonic acid,heptanesulfonic acid, octanesulfonic acid, nonanesulfonic acid,decanesulfonic acid, undecanesulfonic acid, dodecanesulfonic acid,tridecanesulfonic acid, tetradecanesulfonic acid, pentadecanesulfonicacid, hexadecanesulfonic acid, heptadecanesulfonic acid andoctadecanesulfonic acid; haloalkylsulfonic acids such as, for example,fluorometanesulfonic acid, difluorometanesulfonic acid,trifluorometanesulfonic acid, chlorometanesulfonic acid,dichlorometanesulfonic acid, trichlorometanesulfonic acid,bromometanesulfonic acid, dibromometanesulfonic acid,tribromometanesulfonic acid, iodometanesulfonic acid,diiodometanesulfonic acid, triiodometanesulfonic acid,fluoroetanesulfonic acid, difluoroetanesulfonic acid,trifluoroetanesulfonic acid, pentafluoroethanesulfonic acid,chloroethanesulfonic acid, dichloroethanesulfonic acid,trichloroethanesulfonic acid, pentachloroethanesulfonic acid,tribromoethanesulfonic acid, pentabromoethanesulfonic acid,triiodoethanesulfonic acid, pentaiodoethanesulfonic acid,fluoropropanesulfonic acid, trifluoropropanesulfonic acid,heptafluoropropanesulfonic acid, chloropropanesulfonic acid,trichloropropanesulfonic acid, heptachloropropanesulfonic acid,bromopropanesulfonic acid, tribromopropanesulfonic acid,heptabromopropanesulfonic acid, triiodopropanesulfonic acid,heptaiodopropanesulfonic acid, trifluorobutanesulfonic acid,nonafluorobutanesulfonic acid, trichlorobutanesulfonic acid,nonachlorobutanesulfonic acid, tribromobutanesulfonic acid,nonabromobutanesulfonic acid, triiodobutanesulfonic acid,nonaiodobutanesulfonic acid, trifluoropentanesulfonic acid,perfluoropentanesulfonic acid, trichloropentanesulfonic acid,perchloropentanesulfonic acid, tribromopentanesulfonic acid,perbromopentanesulfonic acid, triiodopentanesulfonic acid,periodopentanesulfonic acid, trifluorohexanesulfonic acid,perfluorohexanesulfonic acid, trichlorohexanesulfonic acid,perchlorohexanesulfonic acid, perbromohexanesulfonic acid,periodohexanesulfonic acid, trifluoroheptanesulfonic acid,perfluoroheptanesulfonic acid, trichloroheptanesulfonic acid,perchloroheptanesulfonic acid, perbromoheptanesulfonic acid,periodoheptanesulfonic acid, trifluorooctanesulfonic acid,perfluorooctanesulfonic acid, trichlorooctanesulfonic acid,perchlorooctanesulfonic acid, perbromooctanesulfonic acid,periodooctanesulfonic acid, trifluorononanesulfonic acid,perfluorononanesulfonic acid, trichlorononanesulfonic acid,perchlorononanesulfonic acid, perbromononanesulfonic acid,periodononanesulfonic acid, trifluorodecanesulfonic acid,perfluorodecanesulfonic acid, trichlorodecanesulfonic acid,perchlorodecanesulfonic acid, perbromodecanesulfonic acid,periododecanesulfonic acid, trifluoroundecanesulfonic acid,perfluoroundecanesulfonic acid, trichloroundecanesulfonic acid,perchloroundecanesulfonic acid, perbromoundecanesulfonic acid,periodoundecanesulfonic acid, trifluorododecanesulfonic acid,perfluorododecanesulfonic acid, trichlorododecanesulfonic acid,perchlorododecanesulfonic acid, perbromododecanesulfonic acid,periodododecanesulfonic acid, trifluorotridecanesulfonic acid,perfluorotridecanesulfonic acid, trichlorotridecanesulfonic acid,perchlorotridecanesulfonic acid, perbromotridecanesulfonic acid,periodotridecanesulfonic acid, trifluorotetradecanesulfonic acid,perfluorotetradecanesulfonic acid, trichlorotetradecanesulfonic acid,perchlorotetradecanesulfonic acid, perbromotetradecanesulfonic acid,periodotetradecanesulfonic acid, trifluoropentadecanesulfonic acid,perfluoropentadecanesulfonic acid, trichloropentadecanesulfonic acid,perchloropentadecanesulfonic acid, perbromopentadecanesulfonic acid,periodopentadecanesulfonic acid, perfluorohexadecanesulfonic acid,perchlorohexadecanesulfonic acid, perbromohexadecanesulfonic acid,periodohexadecanesulfonic acid, perfluoroheptadecanesulfonic acid,perchloroheptadecanesulfonic acid, perbromoheptadecanesulfonic acid,periodoheptadecanesulfonic acid, perfluorooctadecanesulfonic acid,perchlorooctadecanesulfonic acid, perbromooctadecanesulfonic acid andperiodooctadecanesulfonic acid; cycloalkylsulfonic acids such as, forexample, cyclopentanesulfonic acid and cyclohexanesulfonic acid;halogenated cycloalkylsulfonic acids such as, for example,2-fluorocyclopentanesulfonic acid, 2-chlorocyclopentanesulfonic acid,2-bromocyclopentanesulfonic acid, 2-iodocyclopentanesulfonic acid,3-fluorocyclopentanesulfonic acid, 3-chlorocyclopentanesulfonic acid,3-bromocyclopentanesulfonic acid, 3-iodocyclopentanesulfonic acid,3,4-difluorocyclopentanesulfonic acid, 3,4-dichlorocyclopentanesulfonicacid, 3,4-dibromocyclopentanesulfonic acid,3,4-diiodocyclopentanesulfonic acid, 4-fluorocyclohexanesulfonic acid,4-chlorocyclohexanesulfonic acid, 4-bromocyclohexanesulfonic acid,4-iodocyclohexanesulfonic acid, 2,4-difluorocyclohexanesulfonic acid,2,4-dichlorocyclohexanesulfonic acid, 2,4-dibromocyclohexanesulfonicacid, 2,4-diiodocyclohexanesulfonic acid,2,4,6-trifluorocyclohexanesulfonic acid,2,4,6-trichlorocyclohexanesulfonic acid,2,4,6-tribromocyclohexanesulfonic acid, 2,4,6-triiodocyclohexanesulfonicacid, tetrafluorocyclohexanesulfonic acid,tetrachlorocyclohexanesulfonic acid, tetrabromocyclohexanesulfonic acidand tetraiodocyclohexanesulfonic acid; aromatic sulfonic acids such as,for example, benzenesulfonic acid, naphthalenesulfonic acid,anthracenesulfonic acid, phenanthrenesulfonic acid and pyrenesulfonicacid; halogenated aromatic sulfonic acids such as, for example,2-fluorobenzenesulfonic acid, 3-fluorobenzenesulfonic acid,4-fluorobenzenesulfonic acid, 2-chlorobenzenesulfonic acid,3-chlorobenzenesulfonic acid, 4-chlorobenzenesulfonic acid,2-bromobenzenesulfonic acid, 3-bromobenzenesulfonic acid,4-bromobenzenesulfonic acid, 2-iodobenzenesulfonic acid,4-iodobenzenesulfonic acid, 2,4-difluorobenzenesulfonic acid,2,6-difluorobenzenesulfonic acid, 2,4-dichlorobenzenesulfonic acid,2,6-dichlorobenzenesulfonic acid, 2,4-dibromobenzenesulfonic acid,2,6-dibromobenzenesulfonic acid, 2,4-diiodobenzenesulfonic acid,2,6-diiodobenzenesulfonic acid, 2,4,6-trifluorobenzenesulfonic acid,3,4,5-trifluorobenzenesulfonic acid, 2,4,6-trichlorobenzenesulfonicacid, 3,4,5-trichlorobenzenesulfonic acid, 2,4,6-tribromobenzenesulfonicacid, 3,4,5-tribromobenzenesulfonic acid, 2,4,6-triiodobenzenesulfonicacid, 3,4,5-triiodobenzenesulfonic acid, pentafluorobenzenesulfonicacid, pentachlorobenzenesulfonic acid, pentabromobenzenesulfonic acid,pentaiodobenzenesulfonic acid, fluoronaphthalenesulfonic acid,chloronaphthalenesulfonic acid, bromonaphthalenesulfonic acid,iodonaphthalenesulfonic acid, fluoroanthracenesulfonic acid,chloroanthracenesulfonic acid, bromoanthracenesulfonic acid andiodoanthracenesulfonic acid; alkyl substituted aromatic sulfonic acidssuch as, for example, p-toluenesulfonic acid, 4-isopropylbenzenesulfonicacid, 3,5-bis(trimethyl)benzenesulfonic acid,3,5-bis(isopropyl)benzenesulfonic acid,2,4,6-tris(trimethyl)benzenesulfonic acid and2,4,6-tris(isopropyl)benzenesulfonic acid; halogenated alkyl aromaticsulfonic acids such as, for example, 2-trifluoromethylbenzenesulfonicacid, 2-trichloromethylbenzenesulfonic acid,2-tribromomethylbenzenesulfonic acid, 2-triiodomethylbenzenesulfonicacid, 3-trifluoromethylbenzenesulfonic acid,3-trichloromethylbenzenesulfonic acid, 3-tribromomethylbenzenesulfonicacid, 3-triiodomethylbenzenesulfonic acid,4-trifluoromethylbenzenesulfonic acid, 4-trichloromethylbenzenesulfonicacid, 4-tribromomethylbenzenesulfonic acid,4-triiodomethylbenzenesulfonic acid,2,6-bis(trifluoromethyl)benzenesulfonic acid,2,6-bis(trichloromethyl)benzenesulfonic acid,2,6-bis(tribromomethyl)benzenesulfonic acid,2,6-bis(triiodomethyl)benzenesulfonic acid,3,5-bis(trifluoromethyl)benzenesulfonic acid,3,5-bis(trichloromethyl)benzenesulfonic acid,3,5-bis(tribromomethyl)benzenesulfonic acid and3,5-bis(triiodomethyl)benzenesulfonic acid; aromatic aliphatic sulfonicacids such as, for example, benzylsulfonic acid, phenethylsulfonic acid,phenylpropylsulfonic acid, phenylbutylsulfonic acid,phenylpentylsulfonic acid, phenylhexylsulfonic acid,phenylheptylsulfonic acid, phenyloctylsulfonic acid andphenylnonylsulfonic acid; halogenated aromatic aliphatic sulfonic acidssuch as, for example, 4-fluorophenylmethylsulfonic acid,4-chlorophenylmethylsulfonic acid, 4-bromophenylmethylsulfonic acid,4-iodophenylmethylsulfonic acid, tetrafluorophenylmethylsulfonic acid,tetrachlorophenylmethylsulfonic acid, tetrabromophenylmethylsulfonicacid, tetraiodophenylmethylsulfonic acid, 4-fluorophenylethylsulfonicacid, 4-chlorophenylethylsulfonic acid, 4-bromophenylethylsulfonic acid,4-iodophenylethylsulfonic acid, 4-fluorophenylpropylsulfonic acid,4-chlorophenylpropylsulfonic acid, 4-bromophenylpropylsulfonic acid,4-iodophenylpropylsulfonic acid, 4-fluorophenylbutylsulfonic acid,4-chlorophenylbutylsulfonic acid, 4-bromophenylbutylsulfonic acid and4-iodophenylbutylsulfonic acid; and alicyclic sulfonic acids such as,for example, campholsulfonic acid and adamantanesulfonic acid etc.; andamong these, fluorine-containing alkylsulfonic acids such as, forexample, trifluorometanesulfonic acid and pentafluoroethanesulfonic acidand p-toluenesulfonic acid are preferable.

The involatile acid catalyst includes preferably an acid having strongacidity, more preferably, for example, sulfuric acid andp-toluenesulfonic acid, among the above examples.

The weak basic substance is not particularly limited as long as it doesnot hydrolyze the ester compound obtained by the method of the presentinvention, and includes, for example, a weak basic substance having apKa of usually 4 to 13, preferably 6 to 12, inorganic weak bases suchas, for example, specifically a carbonate, a hydrogencarbonate, aphosphate and an acetate, for example, amine compounds represented bythe general formula [5]:

(wherein R⁴ to R⁶ are each independently a hydrogen atom, an alkyl groupwhich may have a substituent, an aryl group and an aralkyl group, and R⁴to R⁶ may form a heterocycle with R⁴ to R⁶ and a nitrogen atom bindingto them. Provided that at least one of R⁴ to R⁶ is an alkyl group, anaryl group or an aralkyl group, or a heterocycle formed with R⁴ to R⁶and a nitrogen atom binding to them); and diamine compounds such as, forexample, 1,8-diazabicyclo[5.4. 0]undeca-7-ene and1,4-diazabicyclo[2.2.2]octane (DABCO), etc.

In the general formula [5], the alkyl group of an alkyl group that mayhave a substituent represented by R⁴ to R⁶ includes any of astraight-chained, branched and cyclic group, and usually includes agroup having 1 to 18 carbon atoms, preferably 1 to 8 carbon atoms andspecifically, for example, a methyl group, an ethyl group, a n-propylgroup, an isopropyl group, a n-butyl group, an isobutyl group, asec-butyl group, a tert-butyl group, a n-pentyl group, an isopentylgroup, a sec-pentyl group, a tert-pentyl group, a neopentyl group, a1-methylpentyl group, a n-hexyl group, an isohexyl group, a sec-hexylgroup, a tert-hexyl group, a neohexyl group, a n-heptyl group, anisoheptyl group, a sec-heptyl group, a tert-heptyl group, a neoheptylgroup, a n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, a neooctyl group, a 2-ethylhexyl group, a n-nonylgroup, an isononyl group, a sec-nonyl group, a tert-nonyl group, aneononyl group, a n-decyl group, an isodecyl group, a sec-decyl group, atert-decyl group, a neodecyl group, a n-undecyl group, an isoundecylgroup, a sec-undecyl group, a tert-undecyl group, a neoundecyl group, an-dodecyl group, an isododecyl group, a sec-dodecyl group, atert-dodecyl group, a n-tridecyl group, an isotridecyl group, asec-tridecyl group, a tert-tridecyl group, a neotridecyl group, an-tetradecyl group, an isotetradecyl group, a sec-tetradecyl group, atert-tetradecyl group, a neotetradecyl group, a n-pentadecyl group, anisopentadecyl group, a sec-pentadecyl group, a tert-pentadecyl group, aneopentadecyl group, a n-hexadecyl group, an isohexadecyl group, asec-hexadecyl group, a tert-hexadecyl group, a neohexadecyl group, an-heptadecyl group, an isoheptadecyl group, a sec-heptadecyl group, atert-heptadecyl group, a neoheptadecyl group, a n-octadecyl group, anisooctadecyl group, a sec-octadecyl group, a tert-octadecyl group, aneooctadecyl group, a cyclopropyl group, a cyclobutyl group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctylgroup, a cyclononyl group, a cyclodecyl group, a cycloundecyl group, acyclododecyl group, a cyclotridecyl group, a cyclotetradecyl group, acyclopentadecyl group, a cyclohexadecyl group, a cycloheptadecyl groupand a cyclooctadecyl group etc.

The substituent of the alkyl group which may have a substituent includesan alkyl-substituted amino group. The alkyl-substituted amino groupincludes an amino group of which the hydrogen atom is substituted withan alkyl group having 1 to 3 carbon atoms (for example, a methyl group,an ethyl group, a n-propyl group and an isopropyl group) andspecifically, for example, a dimethylamino group, a diethylamino groupand a dipropylamino group.

The aryl group represented by R⁴ to R⁶ usually includes a group having 6to 15 carbon atoms and specifically, for example, a phenyl group, anaphthyl group and an anthryl group etc.

The aralkyl group represented by R⁴ to R⁶ usually includes a grouphaving 7 to 15 carbon atoms and specifically, for example, a benzylgroup, a phenethyl group, a phenylpropyl group and a naphthylmethylgroup etc.

The heterocycle formed by R⁴ to R⁶ and a nitrogen atom binding to themincludes a 5- or 6-membered ring of usually 1 to 4 nitrogen atoms,preferably 1 to 3 nitrogen atoms, specifically heterocyclic aromaticrings such as, for example, a pyridine ring, a pyrrole ring, a pyrrolinering, a quinoline ring, an indole ring, an isoindoline ring and acarbazole ring, and heterocyclic aliphatic rings such as, for example, apyrrolidine ring, a piperidine ring and a piperazine ring.

The heterocycle may further have an alkyl group having 1 to 3 carbonatoms such as, for example, a methyl group, an ethyl group, a n-propylgroup and an isopropyl group and preferably includes specifically, forexample, 2,3-lutidine, 2,4-lutidine, 2,5-lutidine, 2,6-lutidine,3,4-lutidine, 3,5-lutidine, 2,4,6-collidine,α-collidine(4-ethyl-2-methylpyridine),13-collidine(3-ethyl-4-methylpyridine) and γ-collidine(2,4,6-collidine).

The carbonate as the weak inorganic bases preferably includesspecifically alkaline metal carbonates such as, for example, lithiumcarbonate, sodium carbonate and potassium carbonate, and alkaline-earthmetal carbonates such as, for example, magnesium carbonate, calciumcarbonate and barium carbonate, and more preferably includes, forexample, sodium carbonate and potassium carbonate among these.

The hydrogencarbonate preferably includes specifically alkaline metalhydrogencarbonates such as, for example, sodium hydrogencarbonate andpotassium hydrogencarbonate and more preferably includes sodiumhydrogencarbonate among these.

The phosphate preferably includes specifically, for example, tertiarysodium phosphate and tertiary potassium phosphate etc.

The acetate preferably includes specifically, for example, sodiumacetate and potassium acetate etc.

The amine compound represented by the general formula [5] preferablyincludes specifically primary amines such as, for example, methylamine,ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine,sec-butylamine, tert-butylamine, pentylamine, isopentylamine,sec-pentylamine, tert-pentylamine, neopentylamine, hexylamine,isohexylamine, sec-hexylamine, tert-hexylamine, neohexylamine,heptylamine, octylamine, (2-ethylhexyl)amine, decylamine, cetylamine,cyclopropylamine, cyclobutylamine, cyclopentylamine and cyclohexylamine;secondary amines such as, for example, secondary alkylamines includingfor example, dimethylamine, diethylamine, di-n-propylamine,diisopropylamine, di-n-butylamine, diisobutylamine, di-sec-butylamine,di-tert-butylamine, di-n-pentylamine, diisopentylamine,di-sec-pentylamine, di-tert-pentylamine, dineopentylamine, dihexylamine,diisohexylamine, di-sec-hexylamine, di-tert-hexylamine, dineohexylamine,diheptylamine, dioctylamine, bis(2-ethylhexyl)amine, didecylamine,dicetylamine, dicyclopropylamine, dicyclobutylamine, dicyclopentylamine,dicyclohexylamine, methylethylamine and isopropylethylamine; secondaryarylamines including for example, diphenylamine and dinaphthylamine;secondary aralkylamines such as, for example, dibenzylamine; andsecondary cyclic amines including for example, piperidine, pyrrolidineand piperazine; tertiary amines such as, for example, tertiaryalkylamines including for example, trimethylamine, triethylamine,tri-n-propylamine, triisopropylamine, tri-n-butylamine,triisobutylamine, tri-sec-butylamine, tri-tert-butylamine,tri-n-pentylamine, triisopentylamine, tri-sec-pentylamine,tri-tert-pentylamine, trineopentylamine, trihexylamine,triisohexylamine, tri-sec-hexylamine, tri-tert-hexylamine,trineohexylamine, tricyclopropylamine, tricyclobutylamine,tricyclopentylamine amine, tricyclohexylamine, dimethylethylamine anddiisopropylethylamine; tertiary arylamines including for example,triphenylamine and trinaphthylamine; tertiary aralkylamines includingfor example, tribenzylamine; and tertiary cyclic amines including forexample, pyridine, 2,3-lutidine, 2,4-lutidine, 2,5-lutidine,2,6-lutidine, 3,4-lutidine, 3,5-lutidine, 2,4,6-collidine,α-collidine(4-ethyl-2-methylpyridine),β-collidine(3-ethyl-4-methylpyridine) and γ-collidine(2,4,6-collidine);and, for example, tetramethylethylenediamine.

Even a weak basic substance that is hardly soluble in the reactionsolution related to the present invention can form a salt with an acidcatalyst. Considering, for example, treatment time and treatmenttemperature, however, a weak basic substance that is soluble in thereaction solution is preferable because it can efficiently form a saltwith an acid catalyst. Organic bases such as, for example, triethylamineand pyridine are more preferable as the weak basic substance.

The nonaqueous solvent to be used in the present invention includes asolvent that forms an azeotrope with water and is soluble in the estercompound represented by the general formula [3], obtained by the presentinvention has not high solubility to a salt (neutralized salt) formedfrom an involatile acid catalyst and a weak basic substance, and forexample, a nonprotonic polar solvent or a nonpolar solvent. Thenonprotonic polar solvent includes ethers such as, for example, diethylether, diisopropyl ether, tetrahydrofuran and 1,4-dioxane; halogenatedhydrocarbons such as, for example, methyl chloride, dichloromethane andchloroform; ketones such as, for example, acetone, methyl ethyl ketoneand methyl isobutyl ketone; amides such as, for example,N,N-dimethylformamide, dimethylacetoamide and N-methylpyrrolidone;nitriles such as, for example, acetonitrile, propionitrile andbutyronitrile; and dimethyl sulfoxide. Dichlorometane is preferableamong these. The nonpolar solvent includes aliphatic hydrocarbons suchas, for example, pentane, n-hexane, cyclohexane, heptane and petroleumether; and aromatic hydrocarbons such as, for example, benzene, tolueneand xylene. Toluene or xylene is preferable among these. These solventsmay be used alone or in combination of two or more solvents.

The method for producing an ester compound of the present invention isdescribed in detail as follows.

That is, for example, an alcohol represented by the general formula [1]and a carboxylic acid represented by the general formula [2] are reacted(esterification) without any solvent or in a nonaqueous solvent in thepresence of an acid catalyst, and dehydrated if necessary, and then aweak basic substance is added to the obtained reaction solution to forma salt with the acid catalyst (neutralization) and the salt is removed.The reaction solution is subjected to purification treatment such asdistillation if necessary to obtain an objective ester compoundrepresented by the general formula [3].

While the esterification related to the present invention proceedswithout a reaction solvent, it is preferable to carry out the presentinvention in the coexistence of a nonaqueous solvent because of betterreaction efficiency and easier handling in neutralization of an acidcatalyst.

The amount of an alcohol represented by the general formula [1] to beused in the production method of the present invention is usually 0.5 to50 times by mole, preferably 0.5 to 20 times by mole and more preferably0.8 to 5 times by mole relative to the carboxylic acid, which is a rawmaterial, represented by the general formula [2], although it depends onthe kind and amount of the carboxylic acid or an acid catalyst, orwhether a reaction solvent is present or not.

When the carboxylic acid to be used in the production method of thepresent invention is a dicarboxylic acid represented by the generalformula [12], the amount of the alcohol is usually 1 to 100 times bymole, preferably 1 to 40 times by mole and more preferably 1.6 to 10times by mole relative to the dicarboxylic acid, which is a rawmaterial, although it depends on the kind and amount of the dicarboxylicacid or an acid catalyst, or whether a reaction solvent is present ornot.

When the alcohol to be used in the production method of the presentinvention is an alcohol represented by the general formula [9], theamount of the alcohol is usually 0.25 to 25 times by mole, preferably0.25 to 10 times by mole and more preferably 0.4 to 2.5 times by molerelative to the carboxylic acid, which is a raw material, represented bythe general formula [2], although it depends on the kind and amount ofthe carboxylic acid or an acid catalyst, or whether a reaction solventis present or not.

The amount of the acid catalyst to be used is usually 0.001 to 1.0 timesby mole, preferably 0.01 to 0.8 times by mole and more preferably 0.1 to0.5 times by mole relative to the said alcohol or a compound representedby the general formula [7] when the raw material is the said compound,although it depends on the kind and amount of the alcohol and acarboxylic acid, or whether a reaction solvent is present or not.

The time of heating (refluxing) in esterification is usually 30 minutesto 50 hours, preferably 3 to 10 hours.

The temperature of heating (refluxing) is usually 30 to 300° C.,preferably 30 to 150° C.

Heating (refluxing) is preferably carried out under an atmosphere of aninert gas such as argon and nitrogen.

When the alcohol or/and carboxylic acid as a substance is substitutableas a reaction solvent, the esterification reaction related to thepresent invention may be carried out without any other solvent.

Dehydration is attained by removing the water formed as a by-product inthe esterification of the present invention from the reaction solutionand specifically, carried out, for example, by adding a nonaqueoussolvent to form an azeotrope with water to the reaction solution andthen removing the formed azeotrope from the reaction solution (refluxdehydration treatment). The reflux dehydration treatment may be carriedout, separately from the esterification, but preferably is carried outsimultaneously with reflux heating in the esterification because theobjective ester compound can be efficiently produced by removing waterformed as by-product during the esterification.

Esterification using no solvent is carried out by reflux heating in thecoexistence of a dehydrating agent to be usually used in a reactionsystem in this field (adsorption dehydration treatment). The dehydrationagent includes an agent to be usually used in this field such asmolecular sieve.

Such proper dehydration gives an advantage of easy treatment andincreased efficiency because the water formed as by-product inesterification can be removed from the reaction system beforeneutralization leading to no liquid separation such as extraction.

When the alcohol or carboxylic acid related to the present invention hasa polymerizable double bond in the molecule (that is, when R¹ or/and R²in the general formulae [1] and [2] is an alkenyl group), apolymerization inhibitor is preferably added to the reaction system inorder to prevent polymerization of the alcohol or/and carboxylic acidand the obtained ester compound.

The polymerization inhibitor is not particularly limited as long as itcan prevent polymerization of a raw material alcohol or/and carboxylicacid and a product ester compound, and includes specifically, forexample, hydroquinones such as hydroquinone and methyl hydroquinone;tert-butyl catechol, 2,6-di-tert-butyl-4-methylphenol (BHT),phenothiazine, tri-p-nitrophenylmethyl, di-p-fluorophenylamine,diphenylpicrylhydrazyl, N-(3-N-oxyanilino-1,3-dimethylbutylidene)anilineoxide, benzoquinone, methoquinone, nitrosobenzene, picric acid,dithiobenzoyldisulfide, cupferron, copper chloride (II) andp-methoxyphenol etc. For example, tert-butyl catechol, hydroquinone,2,6-di-tert-butyl-4-methylphenol (BHT), methyl hydroquinone andphenothiazine are preferable among these. These inhibitors may be usedalone or in combination of two or more as appropriate.

A too small amount of a polymerization inhibitor can not effectivelyprevent polymerization, while its too large amount causes a quality andfunctional problem that an increased amount of the polymerizationinhibitor remains in for example, ester compound as the product. Theamount of a polymerization inhibitor, therefore, is usually 0.0001 to10% by weight, preferably 0.005 to 1.0% by weight relative to the totalamount of the alcohol and carboxylic acid as raw materials.

A too small amount of a weak basic substance does not sufficientlyneutralize an acid catalyst causing the acid catalyst to remain in theester compound as impurities, while its too large amount causes anincreased amount of the weak basic substance to remain in the reactionsystem. The amount of a weak basic substance, therefore, is usually 1 to3 times by mole, preferably 1.5 to 2 times by mole relative to the saidacid catalyst to be used.

The temperature of neutralization is usually -50 to 150° C., preferably0 to 50° C.

The time of neutralization is usually 0.5 to 10 hours, preferably 0.5 to2 hours.

A neutralized salt generated by neutralization, that is, a salt formedfrom an acid catalyst and a weak basic substance may be removed asappropriately from the reaction solution by, for example, filtration(adsorption) and liquid separation, the treatment method may be selectedas appropriately according to the state (for example, solid, oil,liquid) of a neutralized salt.

A filter aid may be added to a reaction solution when a neutralized saltis removed from the reaction solution by filtration.

The filter aid to be used for filtration includes, for example,diatomaceous earth, silica gel, activated carbon, hydroxyapatite,alumina and alumina silica.

The amount of an adsorbent to be used is usually 0.001 to 10 times bymole, preferably 0.01 to 1 times by mole relative to the said estercompound represented by the general formula [3].

For example, instead of the weak basic substance related to the presentinvention, a weak basic ion-exchange resin and a polymer having a weakbasic group may be used. When these materials are used as a weak base,they are also able to serve as a filtration aid in neutralization of anacid catalyst in the reaction solution.

Any weak basic ion-exchange resin may be used as long as it has not anadverse effect on the esterification of the present invention, the weakbasic ion-exchange resin includes, for example, an ion-exchange resinwherein a polymer crosslinked by a bifunctional monomer is contained asthe skeleton polymer to which weak basic groups are bonded and the weakbasic groups are exchanged each with various anions (counter ions), andspecifically, for example, a styrene-divinylbenzene copolymer of whichthe aromatic ring is bonded with an amino group. The amino groupincludes every group derived from the amino compound represented by thegeneral formula [5] as the above basic substance.

The polymer having a weak basic group is not particularly limited aslong as it has not an adverse effect on the esterification of thepresent invention and includes a polymer having a weak basic group, forexample, a polymer having a weak basic group derived from the aminocompound represented by the general formula [5].

The base polymer of the polymer having a weak basic group includes, forexample, a polymer or copolymer of a monomer represented by the generalformula [6]:

(wherein R⁷ represents a hydrogen atom, a lower alkyl group, a carboxylgroup, a carboxyalkyl group, an alkyloxycarbonyl group, ahydroxyalkyloxycarbonyl group, a cyano group or a folmyl group; R⁸represents a hydrogen atom, a lower alkyl group, a carboxyl group, analkyloxycarbonyl group, a hydroxyalkyloxycarbonyl group, a cyano groupor a halogen atom; R⁹ represents a hydrogen atom, a lower alkyl group, ahaloalkyl group, a hydroxyl group, an aryl group which may have asubstituent, an aliphatic heterocyclic group, an aromatic heterocyclicgroup, a halogen atom, an alkyloxycarbonyl group, ahydroxyalkyloxycarbonyl group, a sulfo group, a cyano group, acyano-containing alkyl group, an acyloxy group, a carboxyl group, acarboxyalkyl group, an aldehyde group, an amino group, an aminoalkylgroup, a carbamoyl group, a N-alkylcarbamoyl group or a hydroxyalkylgroup, and R⁷ and R⁸ may combine and form an aliphatic ring with anadjacent —C═C—.)

In the general formula [6], the lower alkyl group represented by R⁷ toR⁹ may be any of a straight-chained, branched and cyclic group andincludes, for example, an alkyl group having 1 to 6 carbon atoms andspecifically a methyl group, an ethyl group, a n-propyl group, anisopropyl group, a n-butyl group, an isobutyl group, a tert-butyl group,a sec-butyl group, a n-pentyl group, an isopentyl group, a tert-pentylgroup, a 1-methylpentyl group, a n-hexyl group, an isohexyl group, acyclopropyl group, a cyclopentyl group and a cyclohexyl group etc.

The carboxyalkyl group represented by R⁷ and R⁹ includes, for example, agroup formed by substituting a part of hydrogen atoms of the above loweralkyl group with a carboxyl group and specifically, for example, acarboxymethyl group, a carboxyethyl group, a carboxypropyl group, acarboxybutyl group, a carboxypentyl group and a carboxyhexyl group etc.

The alkyloxycarbonyl group represented by R⁷ to R⁹ includes, forexample, a group having preferably 2 to 11 carbon atoms andspecifically, for example, a methoxycarbonyl group, an ethoxycarbonylgroup, a propoxycarbonyl group, a butoxycarbonyl group, apentyloxycarbonyl group, a hexyloxycarbonyl group, a heptyloxycarbonylgroup, a 2-ethylhexyloxycarbonyl group, an octyloxycarbonyl group, anonyloxycarbonyl group and a decyloxycarbonyl group etc.

The hydroxyalkyloxycarbonyl group represented by R⁷ to R⁹ includes, forexample, a group formed by substituting a part of hydrogen atoms of theabove alkyloxycarbonyl group having 2 to 11 carbon atoms with a hydroxylgroup and specifically, for example, a hydroxymethyloxycarbonyl group, ahydroxyethyloxycarbonyl group, a hydroxypropyloxycarbonyl group, ahydroxybutyloxycarbonyl group, a hydroxypentyloxycarbonyl group, ahydroxyhexyloxycarbonyl group, a hydroxyheptyloxycarbonyl group, ahydroxyoctyloxycarbonyl group, a hydroxynonyloxycarbonyl group and ahydroxydecyloxycarbonyl group etc.

The halogen atom represented by R⁸ and R⁹ includes, for example, afluorine atom, a chlorine atome, a bromine atome and an iodine atom.

The haloalkyl group represented by R⁹ includes, for example, a groupformed by halogenation (for example, fluorination, chlorination,bromination and iodination) of the above lower alkyl group having 1 to 6carbon atoms, represented by R⁷ to R⁹ and specifically, for example, achloromethyl group, a bromomethyl group, a trifluoromethyl group, a2-chloroethyl group, a 3-chloropropyl group, a 3-bromopropyl group, a3,3,3-trifluoropropyl group, a 4-chlorobutyl group, a 5-chloropentylgroup and a 6-chlorohexyl group etc.

The aryl group of an aryl group which may have a substituent includes,for example, a phenyl group, a tolyl group, a xylyl group and a naphthylgroup, and the said substituent includes, for example, an amino group, ahydroxyl group, a lower alkoxy group and a carboxyl group. Thesubstituted aryl group includes specifically, for example, anaminophenyl group, toluidino group, hydroxyphenyl group, methoxyphenylgroup, tert-butoxyphenyl group and carboxyphenyl group.

The aliphatic heterocyclic group includes preferably a 5-membered or6-membered ring having 1 to 3 hetero atoms such as, for example, anitrogen atom, oxygen atom and sulfur atom and specifically, forexample, a 2-oxopyrrolidyl group, a piperidyl group, a piperidino group,a piperazinyl group and a morpholino group etc.

The aromatic heterocyclic group includes preferably a 5-membered or6-membered ring having 1 to 3 hetero atoms such as, for example, anitrogen atom, an oxygen atom and a sulfur atom and specifically, forexample, a pyridyl group, an imidazolyl group, a thiazolyl group, afuryl group and a pyranyl group.

The cyano-containing alkyl group includes, for example, a group formedby substituting a part of hydrogen atoms of the above lower alkyl groupwith a cyano group and specifically, for example, a cyanomethyl group, a2-cyanoethyl group, a 2-cyanopropyl group, a 3-cyanopropyl group, a2-cyanobutyl group, a 4-cyanobutyl group, a 5-cyanopentyl group and a6-cyanohexyl group.

The acyloxy group includes, for example, a group derived from acarboxylic acid having 2 to 20 carbon atoms and specifically, forexample, an acetyloxy group, propionyloxy group, butyryloxy group,pentanoyloxy group, nonanoyloxy group, decanoyloxy group and benzoyloxygroup.

The aminoalkyl group includes a group formed by substituting a part ofhydrogen atoms of the above lower alkyl group with an amino group andspecifically, for example, an aminomethyl group, an aminoethyl group, anaminopropyl group, an aminobutyl group, an aminopentyl group and anaminohexyl group etc.

The N-alkylcarbamoyl group includes a group formed by substituting apart of hydrogen atoms of a carbamoyl group with an alkyl group andspecifically, for example, an N-methylcarbamoyl group, aN-ethylcarbamoyl group, a N-n-propylcarbamoyl group, aN-isopropylcarbamoyl group, a N-n-butylcarbamoyl group and aN-t-butylcarbamoyl group.

The hydroxyalkyl group includes a group formed by substituting a part ofhydrogen atoms of the above lower alkyl group with a hydroxyl group andspecifically, for example, a hydroxymethyl group, a hydroxyethyl group,a hydroxypropyl group, a hydroxybutyl group, a hydroxypentyl group and ahydroxyhexyl group.

The aliphatic ring of an aliphatic ring formed by combining R⁷ and R⁸with an adjacent —C═C— includes, for example, an unsaturated aliphaticring having 5 to 10 carbon atoms that may be either monocyclic orpolycyclic and specifically, for example, a norbornene ring, acyclopentene ring, a cyclohexene ring, a cyclooctene ring and acyclodecene ring.

The monomer represented by the general formula [6] includes specificallyethylenically unsaturated aliphatic hydrocarbons having 2 to 20 carbonatoms such as, for example, ethylene, propylene, butylene andisobutylene; ethylenically unsaturated aromatic hydrocarbons having 8 to20 carbon atoms such as, for example, styrene, 4-methylstyrene,4-ethylstyrene and divinylbenzene; alkenyl esters having 3 to 20 carbonatoms such as, for example, vinyl formate, vinyl acetate, vinylpropionate and isopropenyl acetate; halogen-containing ethylenicallyunsaturated compounds having 2 to 20 carbon atoms such as, for example,vinyl chloride, vinylidene chloride, vinylidene fluoride andtetrafluoroethylene; ethylenically unsaturated carboxylic acids having 3to 20 carbon atoms (these acids may be a salt such as a salt of analkaline metal such as sodium and potassium, and an ammonium salt) suchas, for example, acrylic acid, methacrylic acid, itaconic acid, maleicacid, fumaric acid, crotonic acid, vinylacetic acid, allylacetic acidand vinylbenzoic acid; ethylenically unsaturated carboxylic esters suchas, for example, methyl methacrylate, ethyl methacrylate, propylmethacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, methylacrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexylacrylate, lauryl methacrylate, stearyl acrylate, methyl itaconate, ethylitaconate, methyl maleate, ethyl maleate, methyl fumarate, ethylfumarate, methyl crotonate, ethyl crotonate and methyl 3-butenate;cyano-containing ethylenically unsaturate d compounds having 3 to 20carbon atoms such as, for example, acrylonitrile, methacrylonitrile andallyl cyanide; ethylenically unsaturated amide compounds having 3 to 20carbon atoms such as acrylamide and methacrylamide; ethylenicallyunsaturated aldehydes having 3 to 20 carbon atoms such as acrolein andcrotonaldehyde; ethylenically unsaturated sulfonic acids having 2 to 20carbon atoms (these acids may be a salt such as a salt of an alkalinemetal such as sodium and potassium) such as vinylsulfonic acid and4-vinylbenzenesulfonic acid; ethylenically unsaturated aliphatic amineshaving 2 to 20 carbon atoms such as vinylamine and allylamine;ethylenically unsaturated aromatic amines having 8 to 20 carbon atomssuch as vinylaniline; ethylenically unsaturated aliphatic heterocyclicamines having 5 to 20 carbon atoms such as N-vinylpyrrolidone andvinylpiperidine; ethylenically unsaturated alcohols having 3 to 20carbon atoms such as allyl alcohol and crotyl alcohol; and ethylenicallyunsaturated phenols having 8 to 20 carbon atoms such as 4-vinylphenol.

Introduction of a weak basic group derived from, for example, an aminocompound represented by the general formula [5] to these base polymersmay be carried out as appropriately according to a known method.

An objective ester compound may be purified as appropriately accordingto a known purification method such as distillation and crystallization.The treatment after the reaction may be carried out according to anordinary method of aftertreatment in this field.

The method for producing an ester compound of the present invention canefficiently produce an ester compound without having the problem ofconventional methods that a large amount of waste water generated byneutralization of an acid catalyst with water is harmful in view ofeconomy and environment because an acid catalyst is neutralized by aweak basic substance to form a neutralized salt, which is removed fromthe reaction solution.

Conventional methods which use water for neutralization have a problemof low efficiency in synthesizing a water-soluble ester compound,whereas the production method of the present invention which does notuse water for neutralization can efficiently produce a water-solubleester compound.

Additionally, when water is removed before neutralization, treatmentsuch as liquid separation and washing is not necessary, which makestreatment steps less and improved efficiency possible.

The present invention is described more specifically with reference tothe following examples, to which, however, the invention is not limitedat all.

EXAMPLES Example 1 Synthesis of3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctane 2-methyl-2-propenic acidester

Toluene (2 L), 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctane-1-ol (2.18kg, 6.0 mol), 2-methyl-2-propenic acid(methacrylic acid) (567 g, 6.6mol) and 1,4-dihydroxybenzene(hydroquinone) (6.59 g, 60 mmol) were addedand then p-toluenesulfonic acid monohydrate (148.06 g, 0.78 mol) wasadded thereto. The obtained solution was heated and subjected to refluxdehydration at 115° C. for 5 hours. After reflux dehydration, theobtained reaction solution was cooled to around room temperature andadded with triethylamine (151.5 g, 1.50 mol) was added thereto, stirredfor 0.5 hours and then added with 150 g of silica gel. After stirringfor 0.5 hours, the silica gel was filtered off and the obtained filtratewas added with 1,4-dihydroxybenzene(hydroquinone) (1.32 g, 12.0 mmol),and the solvent was removed in vacuum distillation and then was purifiedin distillation to obtain 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctane2-methyl-2-propenic acid ester (2.44 kg, 94%).

Example 2 Synthesis of Ethyl Methylthioacetate

Toluene (30 ml), ethanol (2.39 g, 169.59 mmol) and methylthioacetic acid(15 g, 141.32 mmol) were added into a 100-ml flask in this order at roomtemperature and then p-toluenesulfonic acid monohydrate (4.03 g, 21.20mmol) was charged thereto. The solution was gently heated and subjectedto reflux dehydration for 3 to 5 hours. After reflux dehydration, thesolution was cooled to around room temperature, added with triethylamine(2.86 g, 28. 26 mmol) at room temperature, stirred and then added withsilica gel. After stirring for a while, the silica gel was filtered off.After the solvent of the filtrate was removed in vacuum distillation,ethyl methylthioacetate (14.81 g, 78%) was isolated in distillation.

Example 3 Synthesis of Ethyl Methoxyacetate

Toluene (100 ml), ethanol (15.34 g, 333.64 mmol) and methoxyacetic acid(25 g, 277.53 mmol) were added into a 200-ml flask in this order at roomtemperature and then p-toluenesulfonic acid monohydrate (7.92 g, 41.63mmol) was charged thereto. The solution was gently heated and subjectedto reflux dehydration for 3 to 5 hours. After reflux dehydration, thesolution was cooled to around room temperature, added with triethylamine(7.02 g, 69.38 mmol) at room temperature, stirred and then added withsilica gel. After stirring for a while, the silica gel was filtered off.After the solvent of the filtrate was removed in vacuum distillation,ethyl methoxyacetate (22.21 g, 68%) was isolated in distillation.

Example 4 Synthesis of ethyl p-tolylacetate

Toluene (100 ml), ethanol (9.20 g, 199.77 mmol) and p-tolylacetic acid(25 g, 166.48 mmol) was added into a 200-ml flask in this order at roomtemperature and then p-toluenesulfonic acid monohydrate (4.75 g, 24.97mmol) was charged thereto. The solution was gently heated and subjectedto reflux dehydration for 3 to 5 hours. After reflux dehydration, thesolution was cooled to around room temperature, added with triethylamine(4.21 g, 41.62 mmol) at room temperature, stirred and then added withsilica gel. After stirring for a while, the silica gel was filtered off.After the solvent of the filtrate was removed in vacuum distillation,ethyl p-tolylacetate (28.09 g, 95%) was isolated in distillation.

Example 5 Synthesis of ethyl 2-furancarboxylate

Toluene (100 ml), ethanol (12.33 g, 267.67 mmol) and 2-furancarboxylicacid (25 g, 223.05 mmol) were added into a 200-ml flask in this order atroom temperature and then p-toluenesulfonic acid monohydrate (6.65 g,34.96 mmol) was charged thereto. The solution was gently heated andsubjected to reflux dehydration for 3 to 5 hours. After refluxdehydration, the solution was cooled to around room temperature, addedwith triethylamine (5.64 g, 55.76 mmol) at room temperature, stirred andthen added with silica gel. After stirring for a while, the silica gelwas filtered off. After the solvent of the filtrate was removed invacuum distillation, ethyl 2-furancarboxylate (27.60 g, 88%) wasisolated in distillation.

Example 6 Synthesis of ethyl 5-chlorovalerate

Toluene (100 ml), ethanol (10.12 g, 219.65 mmol) and 5-chlorovalericacid (25 g, 183.04 mmol) were added into a 200-ml flask in this order atroom temperature and then p-toluenesulfonic acid monohydrate (5.22 g,27.46 mmol) was charged thereto. The solution was gently heated andsubjected to reflux dehydration for 3 to 5 hours. After refluxdehydration, the solution was cooled to around room temperature, addedwith triethylamine (4.63 g, 45.76 mmol) at room temperature, stirred andthen added with silica gel. After stirring for a while, the silica gelwas filtered off. After the solvent of the filtrate was removed invacuum distillation, ethyl 5-chlorovalerate (21.54 g, 72%) was isolatedin distillation.

Example 7 Synthesis of Ethyl Acetylacetate

Toluene (100 ml), ethanol (19.86 g, 431.16 mmol) and pivalic acid (31.64g, 359.30 mmol) were added into a 200-ml flask in this order at roomtemperature and then p-toluenesulfonic acid monohydrate (10.25 g, 53.90mmol) was charged thereto. The solution was gently heated and subjectedto reflux dehydration for 3 to 5 hours. After reflux dehydration, thesolution was cooled to around room temperature, added with triethylamine(9.09 g, 89.83 mmol) at room temperature, stirred and then added withsilica gel. After stirring for a while, the silica gel was filtered off.After the solvent of the filtrate was removed in vacuum distillation,ethyl acetylacetate (13.2 g, 32%) was isolated in distillation.

Example 8 Synthesis of Butyl Acetate

Toluene (100 ml), butanol (7.04 g, 95 mmol) and acetic acid (6.05 g, 100mmol) were added into a 200-ml flask in this order at room temperatureand then p-toluenesulfonic acid monohydrate (2.85 g, 15 mmol) wascharged thereto. The solution was gently heated and subjected to refluxdehydration for 3 to 5 hours. After reflux dehydration, the solution wascooled to around room temperature, added with triethylamine (2.40 g, 25mmol) at room temperature, stirred and then added with silica gel. Afterstirring for a while, the silica gel was filtered off. After the solventof the filtrate was removed in vacuum distillation, butyl acetate (9.87g, 85%) was isolated in distillation.

Example 9 Synthesis of Phenyl Acetate

Toluene (100 ml), phenol (8.94 g, 95 mmol) and acetic acid (6.05 g, 100mmol) were added into a 200-ml flask in this order at room temperatureand then p-toluenesulfonic acid monohydrate (2.85 g, 15 mmol) wascharged thereto. The solution was gently heated and subjected to refluxdehydration for 3 to 5 hours. After reflux dehydration, the solution wascooled to around room temperature, added with triethylamine (2.40 g, 25mmol) at room temperature, stirred and then added with silica gel. Aftercontinuing to stir for a while, the silica gel was filtered off. Afterthe solvent of the filtrate was removed in vacuum distillation, phenylacetate (11.64 g, 90%) was isolated in distillation.

The production method of the present invention, which does not use waterfor neutralization of an acid catalyst, can produce an ester compoundefficiently and industrially without the problem of conventional methodsthat a large amount of waste water is harmful in view of economy andenvironment.

1-18. (canceled)
 19. A method for producing an ester compound havingheterocyclic group(s) represented by a general formula [3]:R¹—OCO—R²   [3] (wherein R¹ represents a heterocyclic group, which mayhave a substituent, and R² represents a heterocyclic group, which mayhave a substituent), which comprises subjecting a carboxylic acidrepresented by a general formula [2]:R²—COOH   [2] (wherein R² is the same as the above) and an alcoholrepresented by a general formula [1]:R¹—OH   [1] (wherein R ¹ is the same as the above) todehydration-condensation reaction using an involatile acid catalyst andthen removing the residual acid catalyst by bringing a weak basicsubstance into contact with the residual acid catalyst.
 20. The methodaccording to claim 19, wherein the acid catalyst is removed by forming asalt of the weak basic substance and the acid catalyst and thenfiltering off the salt.
 21. The method according to claim 19, whereindehydration treatment is carried out in the dehydration-condensationreaction.
 22. The method according to claim 19, wherein the weak basicsubstance is an inorganic weak base, an amine compound represented by ageneral formula [5]:

(wherein R⁴ to R⁶ are each independently a hydrogen atom, an alkyl groupwhich may have a substituent, an aryl group and an aralkyl group; R⁴ toR⁶ may form a heterocycle with R⁴ to R⁶ and a nitrogen atom binding tothem; provided that at least one of R⁴ to R⁶ is an alkyl group, an arylgroup or an aralkyl group, or a heterocycle formed with R⁴ to R⁶ and anitrogen atom binding to them), 1,8-diazabicyclo[5.4.0]undeca-7-ene or1,4-diazabicyclo[2.2.2]octane.
 23. The method according to claim 19,wherein the weak basic substance is triethylamine or pyridine.
 24. Themethod according to claim 19, wherein the involatile acid catalyst is asulfuric acid or a sulfonic acid represented by a general formula [4]:R³—SO₃H   [4] (wherein R³ is an alkyl group, an aryl group or aralkylgroup, which may have a substituent)
 25. The method according to claim24, wherein said acid catalyst is a sulfuric acid or a p-toluenesulfonicacid.
 26. The method according to claim 19, wherein the nonaqueoussolvent is a toluene, a dichloromethane or a cyclohexane.
 27. The methodaccording to claim 20, wherein the filtering treatment is carried out byusing a filter aid.
 28. The method according to claim 27, wherein thefilter aid is a diatomaceous earth, a silica gel, an activated carbon, ahydroxyapatite, an alumina or an alumina silica.
 29. The methodaccording to claim 21, wherein the dehydration treatment is refluxdehydration treatment.
 30. The method according to claim 21, wherein thedehydration treatment is adsorption dehydration treatment.
 31. Themethod according to claim 19, wherein a polymerization inhibitor iscoexsited when R¹ or/and R² is an alkenyl group or an alkynyl group.